Light emitting device

Abstract

A light-emitting device with good performance is provided. The light-emitting device includes a first electrode, a second electrode, a light-emitting layer, and a first layer. The light-emitting layer is located between the first electrode and the second electrode, and the first layer is located between the light-emitting layer and the second electrode. The first layer contains at least one of a first organic compound, a second organic compound, and a metal and a metal compound. The absorption spectrum of the first mixed film containing at least one of the first organic compound, the second organic compound, and a metal and a metal compound has a wavelength region whose absorption intensity is larger than that of the absorption spectrum of the second mixed film containing one of the first organic compound and the second organic compound and at least one of the metal and a metal compound, and whose thickness difference with the first mixed film is less than 10%.

Description

Technical Field

[0001] One aspect of the present invention relates to a light-emitting device, a light-emitting apparatus, a display device, an electronic device, a lighting apparatus, and an electronic device. Note that this aspect of the present invention is not limited to the aforementioned technical fields. The technical field of one aspect of the invention disclosed in this specification relates to an object, method, or manufacturing method. Furthermore, one aspect of the present invention relates to a process, machine, manufacture, or composition of matter. Therefore, specifically, examples of the technical field of one aspect of the present invention disclosed in this specification include semiconductor devices, display devices, liquid crystal display devices, light-emitting devices, lighting apparatuses, energy storage devices, memory devices, imaging devices, input devices (e.g., touch sensors), input / output devices (e.g., touch panels), driving methods for the aforementioned devices, or manufacturing methods for the aforementioned devices. Background Technology

[0002] In recent years, display devices have been applied to various purposes. For example, as large display devices, research and development is underway for home television devices (also known as televisions or television receivers), digital signage, and PID (Public Information Display). As small display devices, research and development is underway for smartphones or tablet terminals with touch panels.

[0003] In addition, there is a demand for high-definition display devices. As devices that require high-definition display devices, such as those for Virtual Reality (VR), Augmented Reality (AR), Substitutional Reality (SR), and Mixed Reality (MR), are already under development.

[0004] As display elements used in display devices, the development of light-emitting devices (also known as light-emitting elements) is increasingly active. Light-emitting devices (also known as EL devices or EL elements) that utilize the electroluminescence (EL) phenomenon, especially organic EL devices that mainly use organic compounds, have the following characteristics: they are easy to achieve in thin and lightweight form; they can respond to input signals at high speed; and they can be driven by a DC constant voltage power supply, etc., so they are preferred for use in display devices.

[0005] To obtain higher-resolution display devices using organic EL devices, a technique for patterning organic compound layers using photolithography has been developed as an alternative to the evaporation method using metal masks. By using photolithography, high-resolution display devices with spacing of several μm between organic compound layers can be obtained (see, for example, Patent Document 1).

[0006] [Patent Document 1] Japanese PCT International Application Translation No. 2018-521459. Summary of the Invention

[0007] It is known that the initial characteristics and reliability of the cathode and organic compound layer in organic EL devices are affected when exposed to atmospheric components such as water and oxygen. Therefore, it is common practice to manufacture organic EL devices in inert gas atmospheres or near-vacuum atmospheres. On the other hand, when manufacturing organic EL devices, as mentioned above, in the process of processing the organic compound layer using lithography techniques such as photolithography (hereinafter, this process is sometimes referred to as the lithography process), the organic compound layer is sometimes exposed to atmospheric components such as water and oxygen, as well as water and chemicals used in photolithography. Therefore, there is a need to develop organic EL devices that include organic compound layers with high resistance to the above-mentioned environments.

[0008] One objective of this invention is to provide a novel light-emitting device. Another objective of this invention is to provide a light-emitting device with good efficiency. Another objective of this invention is to provide a light-emitting device with good reliability. Finally, one objective of this invention is to provide a light-emitting device with both good efficiency and reliability.

[0009] One objective of this invention is to provide a novel light-emitting device manufactured using lithography technology. Another objective of this invention is to provide a light-emitting device manufactured using lithography technology that exhibits good efficiency. A further objective of this invention is to provide a light-emitting device manufactured using lithography technology that exhibits good reliability. Finally, a further objective of this invention is to provide a light-emitting device manufactured using lithography technology that exhibits both good luminous efficiency and high reliability.

[0010] One objective of this invention is to provide a novel light-emitting device that can be used in high-definition display devices. Another objective of this invention is to provide a light-emitting device that is both efficient and usable in high-definition display devices. A further objective of this invention is to provide a light-emitting device that is both reliable and usable in high-definition display devices. Finally, a further objective of this invention is to provide a light-emitting device that is both efficient and reliable and usable in high-definition display devices.

[0011] Note that the description of these objectives does not preclude the existence of other objectives. One aspect of the invention does not necessarily require achieving all of the above objectives. Objectives other than those described above can be extracted from the description, drawings, and claims.

[0012] One aspect of the present invention is a light-emitting device comprising: a first electrode; a second electrode; a light-emitting layer; and a first layer, wherein the light-emitting layer is located between the first electrode and the second electrode, and the first layer is located between the light-emitting layer and the second electrode. The first layer comprises at least one of a first organic compound, a second organic compound, and a metal and a metal compound. Furthermore, the absorption spectrum of the first mixed film comprising at least one of the first organic compound, the second organic compound, and a metal and a metal compound has a wavelength region in which the absorption intensity is larger than that of the absorption spectrum of the second mixed film comprising either the first organic compound or the second organic compound and at least one of the metal and a metal compound, and the difference between the thickness of the second mixed film and the first mixed film is less than 10%.

[0013] One aspect of the present invention is a light-emitting device, comprising: a first electrode; a second electrode; a light-emitting layer; and a first layer, wherein the light-emitting layer is located between the first electrode and the second electrode, and the first layer is located between the light-emitting layer and the second electrode. The first layer comprises at least one of a first organic compound, a second organic compound, and a metal and a metal compound. The absorption spectrum of a first mixed film comprising at least one of the first organic compound, the second organic compound, and a metal and a metal compound has a wavelength region in which the absorption intensity is larger than that of a third mixed film comprising at least one of the first organic compound and a metal and a metal compound and whose thickness difference with the first mixed film is less than 10%. Furthermore, the absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is larger than that of a fourth mixed film comprising at least one of the second organic compound and a metal and a metal compound and whose thickness difference with the first mixed film is less than 10%.

[0014] One aspect of the present invention is a light-emitting device, comprising: a first electrode; a second electrode; a first light-emitting layer; a first layer; and a second light-emitting layer, wherein the first light-emitting layer and the second light-emitting layer are located between the first electrode and the second electrode, the first layer is located between the first light-emitting layer and the second light-emitting layer, the first layer comprises at least one of a first organic compound, a second organic compound, and a metal and a metal compound, and the absorption spectrum of the first mixed film comprising at least one of the first organic compound, the second organic compound, and a metal and a metal compound has a wavelength region whose absorption intensity is larger than that of the absorption spectrum of the second mixed film comprising either the first organic compound or the second organic compound and at least one of the metal and a metal compound, and whose thickness difference with the first mixed film is less than 10%.

[0015] One aspect of the present invention is a light-emitting device, comprising: a first electrode; a second electrode; a first light-emitting layer; a first layer; and a second light-emitting layer, wherein the first light-emitting layer and the second light-emitting layer are located between the first electrode and the second electrode, and the first layer is located between the first light-emitting layer and the second light-emitting layer. The first layer comprises at least one of a first organic compound, a second organic compound, and a metal and a metal compound. The absorption spectrum of a first mixed film comprising at least one of the first organic compound, the second organic compound, and a metal and a metal compound has a wavelength region in which the absorption intensity is larger than that of a third mixed film comprising at least one of the first organic compound and a metal and a metal compound and whose thickness difference with the first mixed film is less than 10%. Furthermore, the absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is larger than that of a fourth mixed film comprising at least one of the second organic compound and a metal and a metal compound and whose thickness difference with the first mixed film is less than 10%.

[0016] In a light-emitting device with the above-described structure according to one aspect of the present invention, the absorption spectrum of the first mixed film has a wavelength region in which its absorption intensity is greater than that of the second mixed film in a region longer than the absorption end on the long wavelength side of the absorption spectrum of the organic compound contained in the second mixed film.

[0017] In a light-emitting device with the above-described structure according to one aspect of the present invention, the absorption spectrum of the first mixed film has a wavelength region in which its absorption intensity is greater than that of the third mixed film in a region longer than the absorption end on the long wavelength side of the absorption spectrum of the film containing the first organic compound, and the absorption spectrum of the first mixed film has a wavelength region in which its absorption intensity is greater than that of the fourth mixed film in a region longer than the absorption end on the long wavelength side of the absorption spectrum of the film containing the second organic compound.

[0018] In a light-emitting device with the above-described structure according to one aspect of the present invention, at least one of the metals and metal compounds comprises a metallic element belonging to any one of groups 3 to 14 of the periodic table.

[0019] In a light-emitting device with the above-described structure according to one aspect of the present invention, at least one of the metals and metal compounds comprises a metal element belonging to Group 3, Group 11 or Group 13 of the periodic table.

[0020] In one embodiment of the present invention, the light-emitting device with the above-described structure further includes: a second layer, wherein the second layer is located between the first layer and the second electrode, the second layer comprising a third organic compound and a fourth organic compound, the third organic compound being an organic compound having a π-electron-rich heteroaromatic ring or an aromatic amine, and the fourth organic compound having at least one of a halogen group and a cyano group.

[0021] In a light-emitting device with the above-described structure according to one aspect of the present invention, the LUMO energy level of the first organic compound is higher than that of the second organic compound.

[0022] In a light-emitting device with the above-described structure according to one aspect of the present invention, the HOMO energy level of the first organic compound is higher than that of the second organic compound.

[0023] In a light-emitting device with the above-described structure according to one aspect of the present invention, both the first organic compound and the second organic compound have heteroaromatic rings.

[0024] In a light-emitting device with the above-described structure according to one embodiment of the present invention, the heteroaromatic rings of the first organic compound and the second organic compound each independently comprise at least one of a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, a triazine ring, an imidazole ring, a pyrazole ring, an oxazole ring, a thiazole ring, and a triazole ring.

[0025] In a light-emitting device with the above-described structure according to one aspect of the present invention, the first organic compound has an electron-donating group.

[0026] In a light-emitting device with the above-described structure according to one embodiment of the present invention, the electron-donating group is at least one selected from alkyl, alkoxy, aryloxy, alkylamino, arylamino, and heterocyclic amino groups.

[0027] According to one aspect of the present invention, a novel light-emitting device can be provided. According to another aspect of the present invention, a light-emitting device with good efficiency can be provided. According to one aspect of the present invention, a light-emitting device with good reliability can be provided. According to one aspect of the present invention, a light-emitting device with both good efficiency and good reliability can be provided.

[0028] According to one aspect of the present invention, a novel light-emitting device manufactured using lithography technology can be provided. According to another aspect of the present invention, a light-emitting device manufactured using lithography technology and possessing good efficiency can be provided. According to one aspect of the present invention, a light-emitting device manufactured using lithography technology and possessing good reliability can be provided. According to one aspect of the present invention, a light-emitting device manufactured using lithography technology and possessing both good luminous efficiency and reliability can be provided.

[0029] According to one aspect of the present invention, a novel light-emitting device that can be used in a high-definition display device can be provided. According to one aspect of the present invention, a light-emitting device that can be used in a high-definition display device and has good efficiency can be provided. According to one aspect of the present invention, a light-emitting device that can be used in a high-definition display device and has good reliability can be provided. According to one aspect of the present invention, a light-emitting device that can be used in a high-definition display device and has good luminous efficiency and reliability can be provided.

[0030] Note that the description of these effects does not preclude the existence of other effects. One aspect of the invention does not necessarily require all of the aforementioned effects. Effects other than those described above can be extracted from the specification, drawings, and claims. Attached Figure Description

[0031] Figure 1A and Figure 1B This is a diagram illustrating the structure of the light-emitting device according to the embodiment; Figure 2 This is a diagram illustrating the structure of the light-emitting device according to the embodiment; Figures 3A to 3C This is the analysis result of the spin density distribution in the ground state of the composite material; Figure 4 This is the analysis result of the spin density distribution in the ground state of the composite material; Figure 5A and Figure 5B This is the analysis result of the electrostatic potential diagram of the organic compound in its ground state; Figures 6A to 6C This is the analysis result of the electrostatic potential diagram of the composite material in its ground state; Figure 7 This is the analysis result of the electrostatic potential diagram of the composite material in its ground state; Figures 8A to 8D This is a diagram illustrating the structure of the light-emitting device according to the embodiment; Figure 9A and Figure 9B These are the top view and cross-sectional view of the light-emitting device; Figures 10A to 10E This is a cross-sectional view illustrating an example of a method for manufacturing a light-emitting device; Figure 11A and Figure 11B This is a cross-sectional view illustrating an example of a method for manufacturing a light-emitting device; Figures 12A to 12D This is a cross-sectional view illustrating an example of a method for manufacturing a light-emitting device; Figures 13A to 13C This is a cross-sectional view illustrating an example of a method for manufacturing a light-emitting device; Figures 14A to 14C This is a cross-sectional view illustrating an example of a method for manufacturing a light-emitting device; Figures 15A to 15C This is a cross-sectional view illustrating an example of a method for manufacturing a light-emitting device; Figure 16A and Figure 16B This is a perspective view showing an example of the structure of a display module; Figure 17A and Figure 17B This is a cross-sectional view showing an example of the structure of a light-emitting device; Figure 18 This is a perspective view showing an example of the structure of a light-emitting device; Figure 19 This is a cross-sectional view showing an example of the structure of a light-emitting device; Figure 20A and Figure 20B This is a diagram illustrating an example of an electronic device; Figures 21A to 21F This is a diagram illustrating an example of an electronic device; Figure 22A and Figure 22B This is a diagram illustrating the structure of the light-emitting device according to an embodiment; Figures 23A to 23C This is a diagram illustrating the structure of the light-emitting device according to an embodiment; Figure 24A and Figure 24B This is a diagram illustrating the structure of the light-emitting device according to an embodiment; Figure 25A and Figure 25B These are the absorption spectra of mixed membrane 1, mixed membrane 2, mixed membrane 3, mixed membrane 4, and single membrane 3; Figure 26A and Figure 26B These are the absorption spectra of single membrane 1 and single membrane 2; Figure 27A and Figure 27B These are the absorption spectra of mixed membrane 5, mixed membrane 6, mixed membrane 7, and single membrane 4; Figure 28A and Figure 28B These are the absorption spectra of mixed membrane 8, mixed membrane 2, mixed membrane 9, mixed membrane 10, and single membrane 3; Figure 29A and Figure 29B These are the absorption spectra of single membrane 1 and single membrane 5; Figures 30A to 30C The LDI-MS spectrum of the co-evaporated film containing Hid2Phen, 6,6'(P-Bqn)2BPy and In is shown. Figure 31 This involves analyzing the planar SEM image of sample 1; Figure 32 This involves analyzing the planar SEM image of sample 2; Figure 33A and Figure 33B This is a cross-sectional STEM image of sample 3; Figure 34A and Figure 34B This is a graph showing the results of the STEM-EDX cross-section analysis of sample 3; Figure 35 This is a cross-sectional STEM image of sample 4a; Figure 36This is a cross-sectional STEM image of sample 4b. Figure 37 This is a cross-sectional STEM image of sample 5a; Figure 38 This is a cross-sectional STEM image of sample 5b. Figure 39 This is a graph showing the results of SIMS analysis of sample 4a and sample 4b; Figure 40 This is a graph showing the results of SIMS analysis of analytical samples 5a and 5b; Figure 41 This is a diagram showing the external quantum efficiency-current density characteristics of analytical devices 1a and 1b; Figure 42 This is a graph showing the current density-voltage characteristics of analytical devices 1a and 1b; Figure 43 This is a graph showing the external quantum efficiency-current density characteristics of analytical devices 2a and 2b; Figure 44 This is a graph showing the current density-voltage characteristics of analytical devices 2a and 2b; Figure 45 This is a graph showing the brightness-current density characteristics of device 1, comparator 2, and comparator 3; Figure 46 This is a diagram showing the brightness-voltage characteristics of device 1, comparator 2, and comparator 3; Figure 47 This is a graph showing the current efficiency-brightness characteristics of device 1, comparator 2, and comparator 3; Figure 48 This is a graph showing the current density-voltage characteristics of device 1, comparator 2, and comparator 3; Figure 49 These are the electroluminescence spectra of device 1, comparator 2, and comparator 3; Figure 50A and Figure 50B These are the absorption spectra of mixed membrane 11, mixed membrane 12, mixed membrane 13, mixed membrane 14 and single membrane 8; Figure 51A and Figure 51B These are the absorption spectra of single membrane 6 and single membrane 7; Figure 52 These are the PL spectra of single membrane 6, single membrane 7, and mixed membrane 14; Figure 53 This is a cross-sectional STEM image of sample 6a; Figure 54 This is a cross-sectional STEM image of sample 6b. Figure 55 This is a graph showing the results of SIMS analysis of sample 6c and sample 6d; Figure 56 This is a graph showing the external quantum efficiency-current density characteristics of analytical device 3 and analytical device 1b; Figure 57 This is a graph showing the current density-voltage characteristics of analytical device 3 and analytical device 1b; Figure 58 This is a graph showing the brightness-current density characteristics of devices 4 and 5; Figure 59 This is a diagram showing the brightness-voltage characteristics of devices 4 and 5; Figure 60 This is a graph showing the current efficiency-brightness characteristics of devices 4 and 5; Figure 61 This is a graph showing the current density-voltage characteristics of devices 4 and 5; Figure 62 These are the electroluminescence spectra of devices 4 and 5; Figure 63 This is a graph showing the brightness changes of devices 4 and 5 relative to the driving time; Figure 64 This is a graph showing the brightness-current density characteristics of device 6 and comparison device 7; Figure 65 This is a diagram showing the brightness-voltage characteristics of device 6 and comparison device 7; Figure 66 This is a graph showing the current efficiency-brightness characteristics of device 6 and comparison device 7; Figure 67 This is a graph showing the current density-voltage characteristics of device 6 and comparison device 7; Figure 68 These are the electroluminescence spectra of device 6 and comparison device 7; Figure 69 This is a graph showing the brightness changes of device 6 and comparison device 7 relative to the driving time; Figure 70A and Figure 70B These are the absorption spectra of mixed membrane 15, mixed membrane 16, mixed membrane 17, and single membrane 9; Figure 71 This is a graph showing the brightness-current density characteristics of device 8; Figure 72 This is a graph showing the brightness-voltage characteristics of device 8; Figure 73 This is a graph showing the current efficiency-brightness characteristics of device 8; Figure 74 This is a graph showing the current density-voltage characteristics of device 8; Figure 75 This is the electroluminescence spectrum of device 8; Figures 76A to 76D This is a diagram illustrating the calculation results according to an embodiment; Figure 77 This is a diagram illustrating the calculation results according to an embodiment. Detailed Implementation

[0032] The embodiments will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the following description, and those skilled in the art will readily understand that its methods and details can be varied in many ways without departing from the spirit and scope of the invention. Therefore, the present invention should not be construed as being limited to the contents described in the embodiments shown below.

[0033] Note that in the structure of the invention described below, the same symbols are used in different figures to show the same parts or parts with the same function, and repeated descriptions are omitted. Furthermore, when showing parts with the same function, the same shading lines are sometimes used without additional symbols.

[0034] Furthermore, for ease of understanding, the positions, sizes, and extents of the constituent elements shown in the accompanying drawings may not always reflect their actual positions, sizes, and extents. Therefore, the disclosed invention is not necessarily limited to the positions, sizes, and extents shown in the accompanying drawings.

[0035] Furthermore, depending on the situation or state, the "film" and "layer" can be interchanged. For example, a "conductive layer" can be changed into a "conductive film." Additionally, for example, an "insulating film" can be changed into an "insulating layer."

[0036] The ordinal numbers such as "first" and "second" used in this specification are added to avoid confusion among the constituent elements and do not indicate a specific order or sequence, such as the order of processes, stacking, or arrangement. Note that for terms in this specification that do not include ordinal numbers, ordinal numbers are sometimes added to the claims to avoid confusion among the constituent elements. Note that for terms in this specification that include ordinal numbers, the ordinal numbers are sometimes omitted in the claims. Furthermore, terms in this specification that include ordinal numbers sometimes have different ordinal numbers added to them in the claims.

[0037] Note that in this specification, etc., devices manufactured using metal masks or FMM (Fine Metal Mask) are sometimes referred to as devices with MM (Metal Mask) structures. Furthermore, in this specification, etc., devices manufactured without metal masks or FMM are sometimes referred to as devices with MML (Metal Mask Less) structures.

[0038] In this specification and the like, a light-emitting device (also referred to as a light-emitting element) includes an EL layer (also referred to as an organic compound layer) between a pair of electrodes. The EL layer includes at least a light-emitting layer.

[0039] Note that in this specification, a conical shape refers to a shape in which at least a portion of the side surface of a constituent element is inclined relative to the substrate surface. For example, it is preferable to have a region where the angle (also called the cone angle) formed by the inclined side surface and the substrate surface is less than 90 degrees. Note that the side surface of the constituent element and the substrate surface do not necessarily have to be completely flat; they can also be approximately planar with slight curvature or approximately planar with slight irregularities.

[0040] Note that in this specification, photoluminescence (PL) spectroscopy refers to the spectrum obtained by fixing the excitation wavelength of the excitation light and scanning the wavelength of the emitted light in fluorescence spectrophotometry. It is sometimes also called emission spectrum. Note that emission spectrum sometimes includes both fluorescent and phosphorescent components. In this specification, emission spectra consisting of fluorescent components are sometimes specifically referred to as fluorescence spectra, and emission spectra consisting of phosphorescent components are particularly referred to as phosphorescence spectra.

[0041] Implementation Method 1 In this embodiment, refer to Figures 1A to 7 This invention describes a light-emitting device according to one aspect of the present invention.

[0042] To illustrate one aspect of the light-emitting device of the present invention, Figure 1A A schematic diagram is shown of two adjacent light-emitting devices, namely light-emitting device 130a and light-emitting device 130b, formed on the same insulating surface as a light-emitting device. Both light-emitting devices 130a and 130b are light-emitting devices that are processed using photolithography on a portion of an organic compound layer. Furthermore, light-emitting devices 130a and 130b are tandem light-emitting devices with a structure in which multiple light-emitting units are stacked with an intermediate layer sandwiched between them.

[0043] The light-emitting device 130a is located on the insulating layer 175 and includes a first electrode 101a having an anode, a second electrode 102 having a cathode, and an organic compound layer 103a. The organic compound layer 103a is located between the first electrode 101a and the second electrode 102. Furthermore, the organic compound layer 103a has a structure in which a first light-emitting unit 501a and a second light-emitting unit 502a are stacked, with an intermediate layer 160a sandwiched between them. The first light-emitting unit 501a includes a first light-emitting layer 113a_1. The intermediate layer 160a includes a first layer 161a and a second layer 162a. The second light-emitting unit 502a includes a second light-emitting layer 113a_2 and an electron injection layer 115. Alternatively, the intermediate layer 160a can be described as being located between the first light-emitting layer 113a_1 and the second light-emitting layer 113a_2.

[0044] In the light-emitting device 130a, all layers of the organic compound layer 103a except for the electron injection layer 115 are fabricated using photolithography. Therefore, the layers of the organic compound layer 103a except for the electron injection layer 115 are separated from the adjacent light-emitting device 130b. Furthermore, the ends (outlines) of the layers of the organic compound layer 103a except for the electron injection layer 115 are aligned or substantially aligned in a direction perpendicular to the substrate. That is, the first light-emitting layer 113a_1, the intermediate layer 160a (first layer 161a and second layer 162a), and the second light-emitting layer 113a_2 are separated from the first light-emitting layer 113b_1, the intermediate layer 160b (first layer 161b and second layer 162b), and the second light-emitting layer 113b_2. In addition, the ends (outlines) of the first light-emitting layer 113a_1, the intermediate layer 160a (first layer 161a and second layer 162a) and the second light-emitting layer 113a_2 are aligned or substantially aligned in a direction perpendicular to the substrate.

[0045] The light-emitting device 130b is located on the insulating layer 175 and includes a first electrode 101b having an anode, a second electrode 102 having a cathode, and an organic compound layer 103b. The organic compound layer 103b is located between the first electrode 101b and the second electrode 102. Furthermore, the organic compound layer 103b has a structure in which a first light-emitting unit 501b and a second light-emitting unit 502b are stacked, sandwiching an intermediate layer 160b. The first light-emitting unit 501b includes a first light-emitting layer 113b_1. The intermediate layer 160b includes a first layer 161b and a second layer 162b. The second light-emitting unit 502b includes a second light-emitting layer 113b_2 and an electron injection layer 115. Alternatively, the intermediate layer 160b can be described as being located between the first light-emitting layer 113b_1 and the second light-emitting layer 113b_2.

[0046] In the light-emitting device 130b, all layers of the organic compound layer 103b except for the electron injection layer 115 are fabricated using photolithography. Therefore, the layers of the organic compound layer 103b except for the electron injection layer 115 are separated (or isolated) from the adjacent light-emitting device 130a. Furthermore, the ends (outlines) of the layers of the organic compound layer 103b except for the electron injection layer 115 are aligned or substantially aligned in a direction perpendicular to the substrate. That is, the first light-emitting layer 113b_1, the intermediate layer 160b (first layer 161b and second layer 162b), and the second light-emitting layer 113b_2 are separated from the first light-emitting layer 113a_1, the intermediate layer 160a (first layer 161a and second layer 162a), and the second light-emitting layer 113a_2. In addition, the ends (outlines) of the first light-emitting layer 113b_1, the intermediate layer 160b (the first layer 161b and the second layer 162b) and the second light-emitting layer 113b_2 are aligned or substantially aligned in a direction perpendicular to the substrate.

[0047] The electron injection layer 115 and the second electrode 102 are preferably formed after processing the layers other than the electron injection layer 115 in the organic compound layer 103a and the layers other than the electron injection layer 115 in the organic compound layer 103b using photolithography. That is, the electron injection layer 115 and the second electrode 102 are preferably continuous layers used by both the light-emitting device 130a and the light-emitting device 130b.

[0048] Using a donor material, such as an alkali metal, alkaline earth metal, or its compound, as the electron injection layer 115 allows for lower voltage in the light-emitting device, which is therefore preferred. However, when processing the organic compound layer containing the aforementioned donor material at the outermost surface of the electron injection layer using lithography, the driving voltage of the light-emitting device may increase significantly or the current efficiency may decrease significantly due to the influence of atmospheric oxygen or water, or the chemicals or water used in the process.

[0049] On the other hand, similar to light-emitting devices 130a and 130b, the light-emitting device is manufactured by forming the electron injection layer 115 and the second electrode 102 after processing each layer other than the electron injection layer 115 in the organic compound layer using lithography. The electron injection layer 115 is not easily affected by oxygen or water in the atmosphere, or by the chemical solution or water used in the process, so a light-emitting device with good characteristics can be realized.

[0050] Furthermore, when processing organic compound layers using lithography, the distance between organic compound layers can be reduced compared to mask evaporation. Specifically, the distance d between each layer of organic compound layer 103a (excluding the electron injection layer 115) and each layer of organic compound layer 103b (excluding the electron injection layer 115) can be reduced to less than 10 μm, 8 μm or less, 5 μm or less, 3 μm or less, 2 μm or less, 1.5 μm or less, 1 μm or less, or 0.5 μm or less. Additionally, for example, by using an LSI exposure apparatus, the distance d can be reduced to, for example, less than 500 nm, less than 200 nm, less than 100 nm, or even less than 50 nm during the process on the silicon wafer.

[0051] Furthermore, preferably, an insulating layer is provided in the gap between each layer of organic compound layer 103a other than the electron injection layer 115 and each layer of organic compound layer 103b other than the electron injection layer 115, thus separating the layers of organic compound layer 103a other than the electron injection layer 115 from each layer of organic compound layer 103b other than the electron injection layer 115. In this case, there is a region where the insulating layer contacts the electron injection layer 115 or the second electrode 102.

[0052] Preferably, in the light-emitting device 130a, the first light-emitting unit 501a, in addition to the first light-emitting layer 113a_1, also includes a hole injection layer 111a, a first hole transport layer 112a_1, and a first electron transport layer 114a_1. Furthermore, the second light-emitting unit 502a, in addition to the second light-emitting layer 113a_2 and the electron injection layer 115, preferably also includes a second hole transport layer 112a_2 and a second electron transport layer 114a_2. Additionally, the intermediate layer 160a may include a third layer 163a between the first layer 161a and the second layer 162a. Note that, as with the second light-emitting unit 502a, when the anode side of the light-emitting unit is in contact with the intermediate layer 160a, the second layer 162a located on the cathode side of the intermediate layer 160a can also be used as a hole injection layer for the second light-emitting unit 502a. Therefore, in this light-emitting unit, a hole injection layer may or may not be provided.

[0053] Preferably, in the light-emitting device 130b, the first light-emitting unit 501b, in addition to the first light-emitting layer 113b_1, also includes a hole injection layer 111b, a first hole transport layer 112b_1, and a first electron transport layer 114b_1. Furthermore, the second light-emitting unit 502b, in addition to the second light-emitting layer 113b_2 and the electron injection layer 115, preferably also includes a second hole transport layer 112b_2 and a second electron transport layer 114b_2. Additionally, the intermediate layer 160b may include a third layer 163b between the first layer 161b and the second layer 162b. Note that, as with the second light-emitting unit 502b, when the anode side of the light-emitting unit is in contact with the intermediate layer 160b, the second layer 162b located on the cathode side of the intermediate layer 160b can also be used as a hole injection layer for the second light-emitting unit 502b. Therefore, in this light-emitting unit, a hole injection layer may or may not be provided.

[0054] In addition, such as Figure 1A As shown, the uppermost layer among all layers except the electron injection layer 115 of the organic compound layer 103a is preferably the second electron transport layer 114a_2. Similarly, the uppermost layer among all layers except the electron injection layer 115 of the organic compound layer 103b is preferably the second electron transport layer 114b_2. When processing the organic compound layers with the second electron transport layer 114a_2 and the second electron transport layer 114b_2 located on the outermost surface using lithography, for example, compared to processing the organic compound layers with the second light-emitting layer 113a_2 and the second light-emitting layer 113b_2 located on the outermost surface, since the second electron transport layer 114a_2 and the second electron transport layer 114b_2 are provided above the second light-emitting layer 113a_2 and the second light-emitting layer 113b_2, they are less susceptible to the influence of atmospheric oxygen or water, or the chemical solutions or water in the process. In other words, it is preferable to use lithography to process at least the layers above the second light-emitting layers 113a_2 and 113b_2 in each organic compound layer, and more preferably to use lithography to process the second electron transport layers 114a_2 and 114b_2 as the top layers. This makes it easier to avoid the degradation of the light-emitting device's characteristics caused by manufacturing using lithography.

[0055] Note that, although in Figure 1A The illustration shows an example where each organic compound layer includes two light-emitting units, but this is not the only embodiment of the invention. Each organic compound layer may also include three or more light-emitting units. By stacking multiple light-emitting units with an intermediate layer sandwiched between a pair of electrodes, high brightness can be achieved while maintaining low current density, thereby enabling a more reliable light-emitting device. Furthermore, a low-power light-emitting device can also be achieved. Additionally, although in Figure 1AAlthough not illustrated, each light-emitting unit may include, in addition to the above-described structure, a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer, and an electron injection layer. Furthermore, each layer may be a stack of two or more layers.

[0056] Note that in this specification, the structure of one of the light-emitting devices 130a and 130b is sometimes shown, but the other of the light-emitting devices 130a and 130b may also have the same structure.

[0057] The intermediate layer 160a sandwiched between the first light-emitting unit 501a and the second light-emitting unit 502a can, for example, inject electrons into one light-emitting unit and holes into the other light-emitting unit when a voltage is applied between the first electrode 101a and the second electrode 102. For example, in Figure 1A In the process, when a voltage is applied such that the potential of the second electrode 102 is higher than the potential of the first electrode 101a, the intermediate layer 160a injects electrons into the first light-emitting unit 501a and holes into the second light-emitting unit 502a.

[0058] exist Figure 1A In the light-emitting device 130a shown, by applying a voltage between a pair of electrodes (first electrode 101a and second electrode 102), electrons are injected from the cathode into the electron injection layer 115, and holes are injected from the anode into the hole injection layer 111a, thereby allowing current to flow. Additionally, electrons are injected from the first layer 161a on the anode side of the intermediate layer 160a into the first electron transport layer 114a_1 of the first light-emitting unit 501a, and holes are injected from the second layer 162a on the cathode side of the intermediate layer 160a into the second hole transport layer 112a_2 of the second light-emitting unit 502a. Furthermore, the injected charge carriers (electrons and holes) recombine to form excitons. When the charge carriers (electrons and holes) in the first light-emitting layer 113a_1 and the second light-emitting layer 113a_2, which contain luminescent material, recombine to form excitons, the luminescent material contained in the first light-emitting layer 113a_1 and the second light-emitting layer 113a_2 is in an excited state, and light can be emitted from the luminescent material.

[0059] In addition, such as Figure 1A As shown, in the preferred intermediate layer 160a, the first layer 161a located on the anode side is adjacent to the first electron transport layer 114a_1 and disposed between the first electron transport layer 114a_1 and the second light-emitting unit 502a. By adopting this structure, electrons can be efficiently injected into the first light-emitting unit 501a.

[0060] Here, in order to reduce the driving voltage of the light-emitting device and achieve efficient light emission, it is preferable to lower the electron injection barrier from the intermediate layer to the first electron transport layer so that electrons generated in the intermediate layer can be smoothly injected and transported to the first electron transport layer. For this purpose, generally, an alkali metal or alkaline earth metal or its compound with a low work function is used as the first layer of the intermediate layer. However, such metals and compounds are easily degraded by oxygen or water in the atmosphere and by water or chemicals used in the lithography process, leading to a significant increase in the driving voltage of the light-emitting device or a significant decrease in current efficiency. Furthermore, it is conceivable to use a metal that is stable to atmospheric oxygen and water and resistant to water and chemicals as the first layer of the intermediate layer. However, such metals are stable but have low electron injection properties, which may create an electron injection barrier between the intermediate layer 160a and the first electron transport layer 114a_1, leading to problems such as an increase in the driving voltage of the light-emitting device and a decrease in luminous efficiency. Therefore, in such a light-emitting device, it is preferable to use a material resistant to water and chemicals used in the process as the intermediate layer.

[0061] in addition, Figure 2 yes Figure 1A The diagram shows a modified example of light-emitting devices 130a and 130b. Both light-emitting devices 130a and 130b are light-emitting devices that are fabricated using lithography to process the entire organic compound layer, including the electron injection layer.

[0062] Figure 2 The organic compound layer 103a of the light-emitting device 130a shown is separated from the adjacent light-emitting device 130b, and includes an electron injection layer 115a having ends (profiles) aligned or substantially aligned with the other layers in a direction perpendicular to the substrate. Furthermore, Figure 2 The organic compound layer 103b of the light-emitting device 130b shown is separate from the adjacent light-emitting device 130a and includes an electron injection layer 115b having ends (profiles) aligned or substantially aligned with the other layers in a direction perpendicular to the substrate. Note that... Figure 2 The light-emitting devices 130a and 130b shown, and their surrounding components, are similar to... Figure 1A The constituent elements shown are the same, so their descriptions are omitted.

[0063] like Figure 2 As shown, in a light-emitting device in which an organic compound layer, including an electron injection layer, is processed using lithography, it is preferable to use a material that is resistant to water and chemicals used in the process for the electron injection layer and the intermediate layer.

[0064] Thus, in one aspect of the light-emitting device of the present invention, a light-emitting device is provided in which at least one of the first layer (161a, 161b) of the above-mentioned intermediate layer (160a, 160b) and the electron injection layer (115, 115a, 115b) adopts the structure of layer 200 described below.

[0065] [Layer 200] like Figure 1B As shown, layer 200 comprises a first organic compound 161_1, a second organic compound 161_2, and a metallic material 161_M, forming a composite material. In this composite material, the first organic compound 161_1 interacts with the metallic material 161_M to form donor levels (SOMO (Singly Occupied Molecular Orbital) or HOMO (Highest Occupied Molecular Orbital) levels), thereby acting as an electron donor for the second organic compound 161_2. By employing this structure, a layer with excellent electron injection characteristics and resistance to atmospheric oxygen and water, as well as water and chemicals used in lithography processes, can be formed.

[0066] Furthermore, layer 200 preferably uses a hybrid layer comprising a first organic compound 161_1, a second organic compound 161_2, and a metallic material 161_M. By giving layer 200 this structure, these substances readily interact, thereby allowing the first organic compound 161_1 and the metallic material 161_M to readily act as electron donors for the second organic compound 161_2. Moreover, compared to a stacked structure, layer 200 with the above structure is less prone to crystallization. Therefore, when processing a portion of the organic compound layer including this layer using lithography, a layer that is not easily crystallized can be formed even when affected by atmospheric oxygen or water, or by the chemical solutions or water used in the process. Furthermore, it is possible to prevent an increase in the driving voltage or a decrease in the current efficiency of the light-emitting device due to crystallization of the intermediate layer or the electron injection layer. Therefore, compared to a stacked structure, a hybrid layer is more suitable for at least one of the intermediate layer and the electron injection layer of a light-emitting device in which a portion of the organic compound layer has been processed using lithography.

[0067] In layer 200, the first organic compound 161_1 interacts with the metallic material 161_M to form a donor level and acts as an electron donor for the second organic compound 161_2. Therefore, by using layer 200 as the first layer (161a, 161b) of the intermediate layers (160a, 160b), electrons generated in the first layer can be easily injected into the first light-emitting unit. Alternatively, electrons generated in the second layer (second layer 162a and second layer 162b) located on the cathode side of the intermediate layer can be easily injected into the first light-emitting unit 501a. Therefore, electron injection into the first light-emitting unit 501a becomes easier, thereby reducing the driving voltage of the light-emitting device and improving the luminous efficiency. Furthermore, by using layer 200 as an electron injection layer (115, 115a, 115b), the electron injection barrier from the second electrode 102 to the organic compound layer (103a, 103b) can be reduced, and the electrons injected from the second electrode 102 can be smoothly injected and transported to the light-emitting layer (113a, 113b) side, thereby obtaining a light-emitting device with reduced driving voltage and high luminous efficiency.

[0068] Metallic material 161_M is at least one of a metal and a metal compound. Furthermore, this at least one metal and metal compound preferably comprises at least one metallic element selected from Groups 3 to 14 of the periodic table. The aforementioned metallic element exhibits low reactivity with atmospheric oxygen and water, as well as with the water and chemicals used in lithography processes. Therefore, when at least one of the metals and metal compounds containing this metallic element is used in a light-emitting device, there is an advantage of less degradation caused by water and oxygen, making it preferred.

[0069] Note that because the metals in groups 3 to 14 of the periodic table have low electron injection capability, it is not easy to improve the characteristics of light-emitting devices when using these metals in typical structures. This sometimes leads to a decrease in luminous efficiency, an increase in driving voltage, and a decrease in driving lifetime. On the other hand, in one aspect of the present invention, layer 200 is a layer comprising a first organic compound 161_1, a second organic compound 161_2, and a metal material 161_M, in which these materials form a composite material. In this composite material, the first organic compound 161_1 interacts with the metal material 161_M to form a donor level (SOMO level or HOMO level), which supplies electrons to the second organic compound 161_2. Therefore, when layer 200 is used as the first layer (161a, 161b) of the intermediate layers (160a, 160b), the electron injection barrier from the intermediate layers (160a, 160b) to the first electron transport layers (114a_1, 114b_1) can be reduced, and electrons generated in the intermediate layers (160a, 160b) can be smoothly injected and transported to the first electron transport layers (114a_1, 114b_1). Furthermore, when this layer 200 is used as the electron injection layer (115, 115a, 115b), the electron injection barrier from the second electrode 102 to the organic compound layer (103a, 103b) can be reduced, and electrons injected from the second electrode 102 can be smoothly injected and transported to the light-emitting layer (113a, 113b). Moreover, it is preferable to form a layer resistant to atmospheric oxygen and water, as well as water and chemicals used in the lithography process. Therefore, one aspect of the present invention can provide a light-emitting device with good moisture resistance, water resistance, oxygen resistance and chemical resistance, low driving voltage and good luminous efficiency.

[0070] Furthermore, the metallic material 161_M more preferably contains a metallic element belonging to an odd group in the periodic table. By adopting this structure, the stability energy is lower and more stable when the first organic compound 161_1 interacts with the metallic material 161_M, and the formed donor level (SOMO level or HOMO level) can be a high level, which is therefore preferred.

[0071] As the first organic compound 161_1 and the second organic compound 161_2, organic compounds capable of forming charge-transfer complexes by combining with the metal material 161_M are preferably selected and used. A charge-transfer complex is a state composed of two or more substances, formed through the migration of charge from one substance to another via interaction. When the first organic compound 161_1, the second organic compound 161_2, and the metal material 161_M are a combination capable of forming a charge-transfer complex, the first organic compound 161_1 readily acts as an electron donor for the second organic compound 161_2 through the metal material 161_M. That is, by combining the first organic compound 161_1 and the second organic compound 161_2 with the metal material 161_M, and by selecting organic compounds capable of forming charge-transfer complexes, electrons can be readily supplied from the donor level formed by the first organic compound 161_1 and the metal material 161_M to the second organic compound 161_2.

[0072] When charge-transfer complexes are formed, new absorption bands different from those of the individual substances forming the complexes are observed. Therefore, by fabricating a film composed of a mixture of the substances and measuring its absorption spectrum, it is possible to determine whether the film is a combination of substances capable of forming charge-transfer complexes.

[0073] For example, the absorption spectrum of the first mixed film comprising the first organic compound 161_1, the second organic compound 161_2, and the metal material 161_M preferably has a wavelength region in which the absorption intensity is larger than that of the second mixed film comprising either the first organic compound 161_1 or the second organic compound 161_2 and the metal material 161_M, and having a thickness equal to that of the first mixed film, wherein the thickness difference between the second mixed film and the first mixed film is, for example, 10% or less. In this case, the first organic compound 161_1, the second organic compound 161_2, and the metal material 161_M can be considered a combination that readily interacts. Furthermore, the first organic compound 161_1, the second organic compound 161_2, and the metal material 161_M can be considered a combination that forms a charge-transfer coordination compound.

[0074] Furthermore, the absorption spectrum of the first mixed film is more preferably located in a wavelength region where its absorption intensity is greater than that of the second mixed film in a region longer than the absorption end on the long wavelength side of the absorption spectrum of the organic compounds contained in the second mixed film, namely, the first organic compound 161_1 and the second organic compound 161_2. In this case, a new absorption band different from that of each substance forming the charge-transfer complex is more clearly generated in the first mixed film, so it is easy to determine that the first organic compound 161_1, the second organic compound 161_2, and the metal material 161_M are a combination that forms a charge-transfer complex.

[0075] For example, the absorption spectrum of a first mixed film comprising a first organic compound 161_1, a second organic compound 161_2, and a metal material 161_M preferably has a wavelength region in which its absorption intensity is larger than that of a third mixed film comprising the first organic compound 161_1 and the metal material 161_M and having the same thickness as the first mixed film, wherein the thickness difference between the third mixed film and the first mixed film is, for example, 10% or less. Furthermore, the absorption spectrum of the first mixed film preferably has a wavelength region in which its absorption intensity is larger than that of a fourth mixed film comprising the second organic compound 161_2 and the metal material 161_M and having the same thickness as the first mixed film, wherein the thickness difference between the fourth mixed film and the first mixed film is, for example, 10% or less. In this case, the first organic compound 161_1, the second organic compound 161_2, and the metal material 161_M can be considered a combination that readily interacts. Furthermore, the first organic compound 161_1, the second organic compound 161_2, and the metal material 161_M can be considered a combination that forms a charge-transfer coordination compound.

[0076] In a light-emitting device with the above-described structure according to one embodiment of the present invention, the absorption spectrum of the first mixed film has a wavelength region in which its absorption intensity is greater than that of the third mixed film in a region longer than the absorption end on the long wavelength side of the absorption spectrum of the film containing the first organic compound 161_1. Furthermore, the absorption spectrum of the first mixed film has a wavelength region in which its absorption intensity is greater than that of the fourth mixed film in a region longer than the absorption end on the long wavelength side of the absorption spectrum of the film containing the second organic compound 161_2. In this case, a new absorption band different from that of each substance forming the charge-transfer complex is more clearly generated in the first mixed film, thus making it easy to determine that the first organic compound 161_1, the second organic compound 161_2, and the metal material 161_M are a combination forming the charge-transfer complex.

[0077] In addition, the absorption end on the longer wavelength side of the absorption spectrum can be calculated by drawing a tangent line at the point where the absolute value of the slope of the longer wavelength side of the peak (or shoulder peak) observed at the longest wavelength of the absorption spectrum is the largest, and then calculating the intersection of the tangent line with the horizontal axis or baseline.

[0078] Note that the intensity of the absorption spectrum depends on the thickness of the sample used for measurement. Therefore, when comparing the absorption spectrum of the first mixed film with the absorption spectra of the second, third, or fourth mixed film, the thickness of the second, third, or fourth mixed film should be equal to that of the first mixed film, for example, the difference in thickness between them is preferably 10% or less, more preferably 7% or less, further preferably 5% or less, and most preferably 3% or less. This allows for a more accurate determination of whether a combination of substances capable of forming a charge-transfer complex is present.

[0079] Furthermore, as the first organic compound 161_1, it is preferable to use an organic compound whose LUMO (Lowest Unoccupied Molecular Orbital) energy level is higher than that of the second organic compound 161_2. This allows the first organic compound 161_1 and the second organic compound 161_2 to readily interact, facilitating the supply of electrons from the donor level formed by the first organic compound 161_1 and the metallic material 161_M to the second organic compound 161_2. Moreover, as the first organic compound 161_1, it is preferable to use an organic compound whose LUMO energy level is 0.05 eV or higher than that of the second organic compound 161_2. Alternatively, as the first organic compound 161_1, it is preferable to use an organic compound whose LUMO energy level is 0.1 eV or higher, and more preferably 0.2 eV or higher, than that of the second organic compound 161_2.

[0080] For example, the LUMO energy level of the organic compound used as the first organic compound 161_1 is preferably -3.0 eV or higher and -2.0 eV or lower, more preferably -2.7 eV or higher and -2.0 eV or lower. This facilitates the supply of electrons from the donor level formed by the first organic compound 161_1 and the metal material 161_M to the second organic compound 161_2. Furthermore, the LUMO energy level of the organic compound used as the second organic compound 161_2 is preferably -3.0 eV or higher and -2.0 eV or lower, more preferably -3.0 eV or higher and -2.5 eV or lower. This improves the electron transport properties of the second organic compound 161_2.

[0081] As the first organic compound 161_1, it is preferable to use an organic compound whose HOMO energy level is higher than that of the second organic compound 161_2. This allows the first organic compound 161_1 and the second organic compound 161_2 to easily interact, readily supplying electrons from the donor level formed by the first organic compound 161_1 and the metal material 161_M to the second organic compound 161_2. Furthermore, the first organic compound 161_1 is preferably an organic compound whose HOMO energy level is 0.05 eV or higher than that of the second organic compound 161_2. Alternatively, the first organic compound 161_1 is preferably an organic compound whose HOMO energy level is 0.1 eV or higher than that of the second organic compound 161_2, more preferably 0.2 eV or higher.

[0082] Note that the HOMO and LUMO energy levels of organic compounds are generally estimated using cyclic voltammetry (CV), photoelectron spectroscopy, optical absorption spectroscopy, and inverse photoelectron spectroscopy. When comparing values ​​of different compounds, it is preferable to use values ​​estimated through the same measurements.

[0083] Furthermore, both the first organic compound 161_1 and the second organic compound 161_2 are preferably organic compounds with electron transport properties. Examples of organic compounds with electron transport properties include organic compounds having heteroaromatic rings. Specifically, π-electron-deficient heteroaromatic rings, such as pyridine rings, pyrazine rings, pyrimidine rings, pyridazine rings, triazine rings, imidazole rings, pyrazole rings, oxazole rings, thiazole rings, triazole rings, and fused rings including these, are preferred because they are electrochemically stable and have high electron transport properties.

[0084] The aforementioned heteroaryl rings are preferred because they contain nitrogen atoms with non-shared electron pairs, which readily interact with metallic material 161_M.

[0085] Furthermore, the first organic compound 161_1 is preferably an organic compound having an electron-donating group. When an organic compound with an electron-donating group is used as the first organic compound 161_1, the first organic compound 161_1 readily interacts with the metal material 161_M. Furthermore, electrons are readily supplied from the donor level formed by the first organic compound 161_1 and the metal material 161_M to the second organic compound 161_2.

[0086] The details of the substances that can be used in metallic material 161_M, first organic compound 161_1, and second organic compound 161_2 will be described later.

[0087] Analysis of the interactions between various organic compounds and metallic materials using quantum chemical calculations. Here, the interaction between metallic material 161_M, first organic compound 161_1, and second organic compound 161_2 is analyzed by quantum chemical calculations.

[0088] <<Estimation of the interactions between various organic compounds and metallic materials>> First, the spin density and electrostatic potential (ESP) of the interaction between the first organic compound 161_1, the second organic compound 161_2, and the metallic material 161_M were analyzed using quantum chemical calculations. In the calculations, 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviated as Pyrrd-Phen) was used as the first organic compound 161_1, 2,9-bis(naphthyl-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviated as NBPhen) or 2,2'-([2,2'-bipyridine]-6,6'-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviated as 6,6'(P-Bqn)2BPy) was used as the second organic compound 161_2, and silver (Ag) was used as the metallic material 161_M. The structural formulas of Pyrrd-Phen, NBPhen, and 6,6'(P-Bqn)2BPy are shown below. Note the additional position numbers for the phenanthrolin ring in the structural formulas of Pyrrd-Phen and NBPhen.

[0089] [Chemical Formula 1] Gaussian09 was used as the quantum chemical calculation program. In the calculations, an HPE SGI8600 was used, and density functional theory (DFT) was employed to calculate the most stable ground-state structures of various organic compounds and composite materials. 6-311G(d,p) and LanL2DZ were used as basis functions, and B3LYP was used as the functional. Note that the total energy of the DFT is expressed as the sum of potential energy, electrostatic energy between electrons, kinetic energy of electrons, and exchange-correlated energy, including all complex electron-electron interactions. In DFT, the calculation accuracy is high because a functional approximation of the exchange-correlated interactions is used, expressed as a function of the single-electron potential in terms of electron density.

[0090] exist Figures 3A to 3CIn this diagram, Pyrrd-Phen is used as the first organic compound 161_1, NBPhen is used as the second organic compound 161_2, and Ag is used as the metallic material 161_M. The analysis results of the ground-state spin density distribution of composites of the first organic compound (Pyrrd-Phen) and the metallic material (Ag), composites of the second organic compound (NBPhen) and the metallic material (Ag), and composites of the first organic compound (Pyrrd-Phen), the second organic compound (NBPhen), and the metallic material (Ag) are shown. In the accompanying figures, spheres represent atoms constituting the compounds, and clouds surrounding the atoms represent atomic units with a density value of 0.003e / a0. 3 (e represents the elementary charge (1e = 1.60218 × 10⁻⁶)) -19 C) and a0 is the Bohr radius (1a0 = 5.29177 × 10⁻⁶). -11 The spin density distribution at time m) represents the local distribution of the compound's doublet ground state. Note that the ground states of Pyrrd-Phen and NBPhen are singlet ground states, therefore no spin density distribution is observed.

[0091] Figure 3A The analysis results of the spin density distribution in the ground state of the composite material of the first organic compound (Pyrrd-Phen) and the metallic material (Ag) are shown. In the doublet ground state of the composite material of the first organic compound (Pyrrd-Phen) and the metallic material (Ag), the first organic compound (Pyrrd-Phen) interacts with the metallic material (Ag), and the metallic material (Ag) is stabilized by coordinating with the nitrogen atoms (N) at the 1 and 10 positions of the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen) which have non-shared electron pairs. Therefore, as Figure 3A As shown, this is partly due to the spin distribution of the unpaired electrons in Ag on a portion of the 1,10-phenanthroline ring in Pyrrd-Phen, particularly on the nitrogen atoms (N) at positions 1 and 10 with non-shared electron pairs. However, due to the weak interaction, most of the spin density is distributed in Ag. Hereinafter, the nitrogen atoms (N) at positions 1 and 10 with non-shared electron pairs in the 1,10-phenanthroline ring are sometimes referred to as N1 and N10.

[0092] Figure 3BThe analysis results of the spin density distribution in the ground state of the composite material of the second organic compound (NBPhen) and the metallic material (Ag) are shown. In the doublet ground state of the composite material of the second organic compound (NBPhen) and the metallic material (Ag), the second organic compound (NBPhen) interacts with the metallic material (Ag), and the metallic material (Ag) is stabilized by coordination at N1 and N10 of the second organic compound (NBPhen). Therefore, as Figure 3B As shown, this is partly due to the spin distribution of unpaired electrons in Ag on a portion of the 1,10-phenanthroline ring of NBPhen, particularly in N1 and N10. However, due to the weak interaction, most of the spin density is distributed on Ag.

[0093] Figure 3C The analysis results of the spin density distribution in the ground state of the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (NBPhen), and the metallic material (Ag) are shown. In the doublet ground state of the composite material, the first organic compound (Pyrrd-Phen), the second organic compound (NBPhen), and the metallic material (Ag) interact, and the metallic material (Ag) is stabilized by being coordinated at N1 and N10 of the first organic compound (Pyrrd-Phen) and the second organic compound (NBPhen). Therefore, as... Figure 3C As shown, the origin lies in the localized spin distribution of unpaired electrons in NBPhen. Furthermore, no spin density distribution is observed in Ag. Therefore, it can be concluded that NBPhen becomes a radical anion state through the interactions of Pyrrd-Phen, NBPhen, and Ag.

[0094] exist Figure 4 In this figure, Ag is used as the metallic material 161_M, Pyrrd-Phen is used as the first organic compound 161_1, and 6,6'(P-Bqn)2BPy is used as the second organic compound 161_2. The analysis results of the spin density distribution in the ground state of the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (6,6'(P-Bqn)2BPy), and the metallic material (Ag) are shown. In the attached figure, spheres represent atoms constituting the compounds, and clouds surrounding the atoms represent isovalues ​​of 0.0004e / a0. 3 The spin density distribution at time is shown, and the local distribution in the doublet ground state of the compound is also shown. Note that the ground state of Pyrrd-Phen and the ground state of 6,6'(P-Bqn)2BPy are singlet ground states, so no spin density distribution is observed.

[0095] In the double ground state of the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (6,6'(P-Bqn)2BPy), and the metallic material (Ag), the first organic compound (Pyrrd-Phen), the second organic compound (6,6'(P-Bqn)2BPy), and the metallic material (Ag) interact. The metallic material (Ag) is stabilized by nitrogen atoms with non-shared electron pairs located in the N1 and N10 of the first organic compound (Pyrrd-Phen) and the pyridine ring and benzo[h]quinazoline ring of the second organic compound (6,6'(P-Bqn)2BPy). Therefore, as Figure 4 As shown, the spin density distribution of unpaired electrons in Ag is locally located in 6,6'(P-Bqn)2BPy. Furthermore, no spin density distribution is observed in Ag. Therefore, it can be concluded that the second organic compound (6,6'(P-Bqn)2BPy) becomes a radical anion state through the interactions of Pyrrd-Phen, 6,6'(P-Bqn)2BPy, and Ag.

[0096] Next, in Figure 5A , Figure 5B , Figure 6A , Figure 6B and Figure 6C In this diagram, Ag is used as the metallic material 161_M, Pyrrd-Phen is used as the first organic compound 161_1, and NBPhen is used as the second organic compound 161_2. The analysis results of electrostatic potential diagrams at the ground states of the first organic compound (Pyrrd-Phen), the second organic compound (NBPhen), the composite material of the first organic compound (Pyrrd-Phen) and the metallic material (Ag), the composite material of the second organic compound (NBPhen) and the metallic material (Ag), and the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (NBPhen), and the metallic material (Ag) are shown. In the attached diagram, spheres represent atoms constituting the compounds, and clouds surrounding the atoms represent a density of 0.003e / a0 in atomic units. 3 The electron density distribution (ESP) at time. ESP is the interaction energy between a positive point charge of unit charge and the electron distribution of a molecule. In an electrostatic potential diagram, ESP in an isoelectronic density surface is represented by color. Red and blue represent regions with negative and positive ESP, respectively. Atoms in regions with negative ESP have negative charges, and atoms in regions with positive ESP have positive charges. Note that because... Figure 5A and Figure 5B as well as Figures 6A to 6CSince it is a grayscale image, in order to represent the areas where ESP is negative and the areas where ESP is positive, a thick dashed line surrounds the parts represented by dark red (i.e., the areas where ESP is negative), and a thin dotted line surrounds the parts represented by dark blue (i.e., the areas where ESP is positive).

[0097] Figure 5A The analytical results of the electrostatic potential diagram of the first organic compound (Pyrrd-Phen) in its ground state are shown. From... Figure 5A It can be seen that the ESP around N1 and N10 in the singlet ground state of the first organic compound (Pyrrd-Phen) is negative. Furthermore, in atomic units, the Mulliken partial charge of N1 and N10 is -0.29e, which is negative. Therefore, it can be concluded that N1 and N10 have negative partial charges in the singlet ground state of the first organic compound (Pyrrd-Phen).

[0098] Figure 5B The analytical results of the electrostatic potential diagram of the second organic compound (NBPhen) in its ground state are shown. From... Figure 5B It can be seen that the ESP around N1 and N10 in the singlet ground state of the second organic compound (NBPhen) is negative. Furthermore, in atomic units, the Mulliken partial charge of N1 and N10 is -0.34e, which is negative. Therefore, it can be concluded that N1 and N10 in the singlet ground state of the second organic compound (NBPhen) have negative partial charges.

[0099] Figure 6A The analysis results of the electrostatic potential diagram of the composite material of the first organic compound (Pyrrd-Phen) and the metallic material (Ag) in the ground state are shown. In the doublet ground state of the composite material, the first organic compound (Pyrrd-Phen) interacts with the metallic material (Ag), and the metallic material (Ag) is stabilized by coordination at N1 and N10 of the first organic compound (Pyrrd-Phen). From the results, it can be seen that... Figure 6A As shown, the ESP around N1, N10, and Ag in Pyrrd-Phen is negative. Furthermore, in atomic units, the Mulliken partial charge of N1 and N10 is -0.37e, which is negative. Additionally, in atomic units, the Mulliken partial charge of Ag is -0.18e, which is also negative. Therefore, it can be concluded that in the double ground state of the composite material of the first organic compound (Pyrrd-Phen) and the metallic material (Ag), N1, N10, and Ag possess negative partial charges.

[0100] Figure 6BThe analysis results of the electrostatic potential diagram of the composite material of the second organic compound (NBPhen) and the metallic material (Ag) in the ground state are shown. In the doublet ground state of the composite material of the second organic compound (NBPhen) and the metallic material (Ag), the second organic compound (NBPhen) interacts with the metallic material (Ag), and the metallic material (Ag) is stabilized by coordination at N1 and N10 of the second organic compound (NBPhen). From the results, it can be seen that, Figure 6B As shown, the ESP around N1, N10, and Ag in NBPhen is negative. Furthermore, in atomic units, the Mulliken partial charges of N1 and N10 are -0.45e and -0.39e, respectively, and the Mulliken partial charge of the metallic material (Ag) is -0.06e, which is negative. Therefore, it can be concluded that in the doublet ground state of the composite material of the second organic compound (NBPhen) and the metallic material (Ag), N1, N10, and Ag possess negative partial charges.

[0101] Figure 6C The analysis results of the electrostatic potential diagram in the ground state of the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (NBPhen), and the metallic material (Ag) are shown. In the doublet ground state of the composite material, the first organic compound (Pyrrd-Phen), the second organic compound (NBPhen), and the metallic material (Ag) interact, and the metallic material (Ag) is stabilized by being coordinated at N1 and N10 of the first organic compound (Pyrrd-Phen) and the second organic compound (NBPhen). From the results, it can be seen that, Figure 6C As shown, positive ESP is mainly distributed around Ag and Pyrrd-Phen, while negative ESP is mainly distributed around NBPhen. Furthermore, it can be seen that the ESP around N1 and N10 of NBPhen is negative, while the ESP of Ag is positive. Additionally, in atomic units, the Mulliken charge of N1 and N10 of NBPhen is -0.52e, which is negative, while the Mulliken charge of Ag is 0.39e, which is positive. Therefore, it can be concluded that the charge of Ag atoms is distributed around N1 and N10 of NBPhen.

[0102] Next, in Figure 7In this figure, Ag is used as the metallic material 161_M, Pyrrd-Phen is used as the first organic compound 161_1, and 6,6'(P-Bqn)2BPy is used as the second organic compound 161_2. The analysis results of the ground-state electrostatic potential diagrams of the composite materials of the first organic compound (Pyrrd-Phen), the second organic compound (6,6'(P-Bqn)2BPy), and the metallic material (Ag) are shown. In the attached figure, spheres represent atoms constituting the compounds, and clouds surrounding the atoms represent isovalues ​​of 0.0004 [electrons / au]. 3 The electron density distribution ESP at [time]. Figure 7 In order to show the areas where ESP is negative and the areas where ESP is positive, a thick dashed line surrounds the dark red area (i.e., the area where ESP is negative), and a thin dotted line surrounds the dark blue area (i.e., the area where ESP is positive).

[0103] In the double ground state of the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (6,6'(P-Bqn)2BPy), and the metal material (Ag), the first organic compound (Pyrrd-Phen), the second organic compound (6,6'(P-Bqn)2BPy), and the metal material (Ag) interact. The metal material (Ag) is stabilized by nitrogen atoms with non-shared electron pairs located in the N1 and N10 of the first organic compound (Pyrrd-Phen) and the pyridine ring and benzo[h]quinazoline ring of the second organic compound (6,6'(P-Bqn)2BPy). From the results, it can be seen that... Figure 7 As shown, positive ESPs are mainly distributed in Ag and Pyrrd-Phen, while negative ESPs are mainly distributed in 6,6'(P-Bqn)2BPy. Furthermore, the ESPs of nitrogen atoms with non-shared electron pairs in the pyridine ring and benzo[h]quinazoline ring of 6,6'(P-Bqn)2BPy are negative, while the ESP of Ag is positive. Additionally, the Mulliken charge of this Ag atom is +0.372e in atomic units.

[0104] Therefore, it can be seen that the first organic compound 161_1 interacts with the metal material 161_M to form an electron donor, and also acts as an electron donor for the second organic compound 161_2, which has electron transport properties. In one aspect of the invention, by using the composite material of this combination in at least one of the intermediate layer and the electron injection layer, at least one of the intermediate layer and the electron injection layer with good electron injection characteristics and resistance to atmospheric oxygen and water, as well as water and chemicals used in the lithography process, can be formed. Therefore, a light-emitting device with reduced driving voltage and high luminous efficiency can be obtained.

[0105] <<Estimation of SOMO level or stabilization energy>> Next, quantum chemistry calculation is used to estimate the stabilization energy when the metal material 161_M, the first organic compound 161_1 and the second organic compound 161_2 interact with each other, and the SOMO level or HOMO level formed at this time. Note that in the calculation, silver (Ag), aluminum (Al), copper (Cu) or indium (In) is used as the metal material 161_M, Pyrrd-Phen is used as the first organic compound 161_1, and 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P), NBPhen, 6,6'-(P-Bqn)2BPy, 4',4''''-(1,4-phenylene)bis(2,2':6',2''-terpyridine) (abbreviation: tPy2P) or 2,4,6-tris(2-pyridyl)-1,3,5-triazine (abbreviation: 2Py3Tzn) is used as the second organic compound 161_2.

[0106] The structural formulas of Pyrrd-Phen, mPPhen2P, NBPhen, 6,6'-(P-Bqn)2BPy, tPy2P and 2Py3Tzn are shown below. In addition, 6,6'-(P-Bqn)2BPy, tPy2P and 2Py3Tzn have two or more heteroaromatic rings which are bonded or fused to each other, so that the organic compound has a total of three or more heteroatoms. On the other hand, NBPhen has two or more heteroaromatic rings which are bonded or fused to each other, and the total number of heteroatoms in this organic compound is less than 3.

[0107] [Chemical Formula 2] Gaussian09 was used as the quantum chemical calculation program. The calculations were performed using an SGI8600 manufactured by HPE. First, density functional theory (DFT) was used to calculate the ground states of the first organic compound 161_1, the second organic compound 161_2, and the metallic material 161_M, as well as the most stable structures in the ground states of the composite materials of the first organic compound 161_1 and the metallic material 161_M, the composite materials of the second organic compound 161_2 and the metallic material 161_M, and the composite materials of the first organic compound 161_1, the second organic compound 161_2, and the metallic material 161_M. 6-311G(d,p) and LanL2DZ were used as basis functions, and B3LYP was used as the functional. Next, the stability energy was calculated based on the difference between the total energy of the composite material of the organic compound and the metallic element and the sum of the total energies of the organic compound and the metallic element. That is, (stability energy) = (total energy of the composite material of the organic compound and the metallic element) - (total energy of the organic compound) - (total energy of the metallic element).

[0108] The calculated results show the stability energy of the composite material of the first organic compound 161_1, the second organic compound 161_2, and the metallic material 161_M.

[0109] Table 1 shows the calculation results for the following composite materials: Pyrrd-Phen as the first organic compound 161_1, mPPhen2P as the second organic compound 161_2, and Ag as the metallic material 161_M. Table 1 shows the stability energy of the composite material of Ag and Pyrrd-Phen, and the stability energy of the composite material of mPPhen2P and Ag.

[0110] [Table 1] Table 1 shows that the stability energies of the Pyrrd-Phen and Ag composites and the mPPhen2P and Ag composites are negative. Furthermore, the Pyrrd-Phen and mPPhen2P composites are more energy-stable when interacting with Ag compared to the case where no interaction occurs. However, the absolute values ​​of the stability energies are small, indicating that the interaction between either Pyrrd-Phen or mPPhen2P and Ag is relatively weak.

[0111] On the other hand, as shown in Table 1, the stability energy of the composite material of Pyrrd-Phen, mPPhen2P, and Ag is lower than that of the composite material of Pyrrd-Phen and Ag and the composite material of mPPhen2P and Ag, and is energy stable. Therefore, the stability energy of the composite material of metal material 161_M, the first organic compound 161_1, and the second organic compound 161_2 is preferably -0.50 eV or less, more preferably -1.0 eV or less, -2.0 eV or less, -3.0 eV or less, or -4.0 eV or less.

[0112] Next, Table 2 shows the results of calculations for the following composite materials: Pyrrd-Phen is used as the first organic compound 161_1, mPPhen2P is used as the second organic compound 161_2, and a metal belonging to an odd group (Group 3, Group 5, Group 7, Group 9, Group 11 or Group 13) is used as the metallic material 161_M, specifically Al, Ag, Cu or In.

[0113] [Table 2] Table 2 shows that the stability energy of the composite materials of Pyrrd-Phen, mPPhen2P, and Al is below -4.0 eV; the stability energy of the composite materials of Pyrrd-Phen, mPPhen2P, and Cu is below -3.0 eV; and the stability energy of the composite materials of Pyrrd-Phen, mPPhen2P, and Ag, as well as the composite materials of Pyrrd-Phen, mPPhen2P, and In, is below -1.0 eV. Therefore, when using metal elements belonging to odd-numbered groups, the composite materials of the first organic compound 161_1, the second organic compound 161_2, and the metal material 161_M have stability energies below -1.0 eV, -3.0 eV, or -4.0 eV, respectively, and are thus more energy-stable and preferred. Furthermore, the calculated SOMO energy levels of these composite materials are higher than the calculated HOMO energy levels of Pyrrd-Phen (-5.65 eV) and mPPhen2P (-5.88 eV). A higher SOMO energy level allows for the formation of layers with superior electron injection properties when used as intermediate and electron-injection layers, making it a more desirable option.

[0114] Next, calculations were performed on the following composite materials: Pyrrd-Phen was used as the first organic compound 161_1, 6,6'(P-Bqn)2BPy, tPy2P, 2Py3Tzn or NBPhen was used as the second organic compound 161_2, and metals belonging to Group 11 and Group 13 were used as the metallic material 161_M, specifically Ag, Al or In.

[0115] Pyrrd-Phen was used as the first organic compound 161_1, 6,6'(P-Bqn)2BPy or NBPhen was used as the second organic compound 161_2, and Ag was used as the metallic material 161_M. Table 3 shows the calculation results for this case. Note that Table 3 also shows the calculation results for composite materials using Pyrrd-Phen and Ag, composite materials using 6,6'(P-Bqn)2BPy and Ag, and composite materials using NBPhen and Ag.

[0116] [Table 3] Furthermore, Table 4 shows the LUMO and HOMO levels for Pyrrd-Phen, 6,6'(P-Bqn)2BPy, tPy2P, 2Py3Tzn, and NBPhen. Note that the HOMO and LUMO levels in the table are calculated values, and sometimes the absolute values ​​differ from the measured values.

[0117] [Table 4] Table 3 shows that the stability energy of the composite material of Pyrrd-Phen, 6,6'(P-Bqn)2BPy, and Ag is negative and has a large absolute value. This indicates that the composite material is more energy-stable when interacting with Pyrrd-Phen, 6,6'(P-Bqn)2BPy, and Ag compared to the case where no interaction occurs. Furthermore, Tables 3 and 4 show that the SOMO energy level of this composite material is higher than the HOMO energy levels of Pyrrd-Phen and 6,6'(P-Bqn)2Bpy, and the difference between the composite material and the LUMO energy levels of Pyrrd-Phen and 6,6'(P-Bqn)2Bpy is small. Therefore, by using this composite material as an intermediate layer or electron injection layer, a layer with excellent electron injection properties can be achieved, making it a preferred choice.

[0118] Furthermore, as shown in Table 3, the stability energy of the composite materials of Pyrrd-Phen, NBPhen, and Ag is negative, and the Pyrrd-Phen, NBPhen, and Ag are more energy stable when they interact with each other compared to when they do not interact.

[0119] Furthermore, the SOMO energy level of the composite material containing 6,6'(P-Bqn)2BPy and Ag is low, at -2.86 eV. On the other hand, the SOMO energy level of the composite material containing 6,6'(P-Bqn)2BPy, Pyrrd-Phen, and Ag is higher, at -2.35 eV, thus exhibiting excellent electron injection properties. In addition, the stability energy of the composite material containing 6,6'(P-Bqn)2BPy and Ag is -0.73 eV, while the stability energy of the composite material containing 6,6'(P-Bqn)2BPy, Pyrrd-Phen, and Ag is more stable, at -1.29 eV.

[0120] Furthermore, the Ag and NBPhen composite exhibits a relatively low SOMO energy level of -3.26 eV. Conversely, the composite containing Ag, NBPhen, and Pyrrd-Phen demonstrates a high SOMO energy level of -2.50 eV, indicating superior electron injection performance. Additionally, the Ag and NBPhen composite has a stability energy of -0.23 eV, while the Ag, NBPhen, and Pyrrd-Phen composite exhibits greater stability at -1.26 eV.

[0121] Pyrrd-Phen is used as the first organic compound 161_1, 6,6'(P-Bqn)2BPy, tPy2P, 2Py3Tzn or NBPhen is used as the second organic compound 161_2, and In or Al is used as the metallic material 161_M. Table 5 shows the calculation results at this time.

[0122] [Table 5] As shown in Table 5, the stability energy of composite materials of In or Al, Pyrrd-Phen, and tPy2P, 2Py3Tzn or NBPhen is negative and the absolute value is large.

[0123] Thus, the composite material containing metals belonging to Groups 11 and 13, the first organic compound 161_1, and the second organic compound 161_2 exhibits stable stability and is therefore preferred. Furthermore, the SOMO level formed at this point is high and has excellent electron injection properties, making it also preferred.

[0124] Based on the above calculation results, the composite material using the first organic compound 161_1, the second organic compound 161_2, and the metal material 161_M is stable and has excellent electron injection properties, so it can be said that it is suitable for use as an intermediate layer or an electron injection layer.

[0125] Note that, considering the manufacturing process of light-emitting devices, the organic compound layer, especially the intermediate layer, is generally deposited using vacuum evaporation in many cases. As the material used in this process, materials that can be easily vacuum-deposited, i.e., materials with low melting points, are preferred. Metals belonging to Group 11 and Group 13 have low melting points, making them suitable for vacuum evaporation. Furthermore, metals belonging to Group 11 and Group 13 are stable to atmospheric oxygen and water, making them preferred. Additionally, vacuum evaporation allows for easy mixing of metal atoms and organic compounds, which is also preferred.

[0126] Furthermore, Ag, Al, and In can all be used as cathode materials. Using the same materials for both the intermediate layer and the cathode allows for easy fabrication of light-emitting devices, making it a preferred option. Additionally, it reduces the manufacturing cost of the light-emitting device.

[0127] Analysis of Composite Materials of Metals and Organometallic Compounds In addition, in one aspect of the light-emitting device of the present invention, at least one of the intermediate layer and the electron injection layer of layer 200 can be measured as a composite material in which the first organic compound 161_1, the second organic compound 161_2 and the metal material 161_M interact.

[0128] Specifically, a film is prepared to be formed in the same proportion as the intermediate layer used in the light-emitting device, and the film is measured using mass spectrometry methods such as Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), Laser Desorption / Ionization Mass Spectrometry (LDI-MS), and Matrix Assisted Laser Desorption / Ionization Mass Spectrometry (MALDI-MS).

[0129] According to the results of this mass spectrometry analysis, when the mass number of the first organic compound 161_1 is M1, the mass number of the second organic compound 161_2 is M2, and the mass number of the metal material 161_M is M3, positive ions with a mass-to-charge ratio of m / z of M1+M2+M3 or M1+M2+M3+1 can be detected. Furthermore, when measuring positive ions using these mass spectrometry methods, ions originating from compounds contained in the membrane, substituents desorbed from the compounds, compounds desorbed from the substituents, and their associated ions can be detected. Therefore, for example, when the mass number of the metal desorbed from the metal compound is 31, positive ions with m / z of M1+M2+31 or M1+M2+31+1 can be detected.

[0130] Next, details of the substances that can be used in metallic material 161_M, first organic compound 161_1, and second organic compound 161_2 will be described.

[0131] <Metallic Materials 161_M> As described above, metallic material 161_M is at least one of a metal and a metal compound. Furthermore, the at least one of the metal and metal compound preferably comprises at least one metallic element selected from Groups 3 to 14 of the periodic table.

[0132] For metallic elements (i.e., transition elements) in groups 3 to 11 of the periodic table, the following can be used: Group 3 elements containing lanthanum such as yttrium (Y), europium (Eu), and ytterbium (Yb); Group 4 elements such as titanium (Ti); Group 5 elements such as vanadium (V); Group 5 elements such as chromium (Cr); Group 7 elements such as manganese (Mn); Group 8 elements such as iron (Fe); Group 9 elements such as cobalt (Co); Group 10 elements such as nickel (Ni) and platinum (Pt); and Group 11 elements such as copper (Cu), silver (Ag), and gold (Au). Transition elements have low reactivity with atmospheric components such as water and oxygen, so they are preferred.

[0133] As metal elements belonging to groups 12 to 14, group 12 elements such as zinc (Zn), earth metals (group 13 elements) such as aluminum (Al) and indium (In), and group 14 elements such as tin (Sn) can be used.

[0134] Among the aforementioned metallic elements, those belonging to odd-numbered groups (Groups 3, 5, 7, 9, 11, and 13) of the periodic table are preferred. Of these metallic elements, those containing an unpaired electron in their outermost orbital readily form SOMO with the first organic compound 161_1, and are therefore particularly preferred.

[0135] Furthermore, among the aforementioned metallic elements, metallic materials containing elements with low melting points that can be deposited using vacuum evaporation are preferred as they readily form mixed layers with organic compounds. Specifically, for example, metals belonging to Group 11 and Group 13 elements have low melting points, making them suitable for vacuum evaporation. Moreover, metals belonging to Group 11 and Group 13 elements are stable to atmospheric oxygen and water, making them preferred as well.

[0136] Furthermore, when the metallic material 161_M is a metallic compound, specific examples include metal oxides and metal nitrides that contain at least one of the aforementioned metallic elements.

[0137] Note that even if a metal is used as a raw material when forming layer 200, it may be oxidized into a metal oxide during processes such as deposition or atmospheric release. In this case, layer 200 may contain both a metal and a metal compound.

[0138] Furthermore, the content of the metal material 161_M in layer 200 is preferably 0.1% or more and 5% or less by volume, more preferably 1% or more and 5% or less. When layer 200 is formed by vacuum evaporation, setting its content to the above-mentioned content allows for the formation of a uniform film and improves the characteristics of the light-emitting device, thus it is preferred.

[0139] For example, the elemental content in the membrane can be analyzed using secondary ion mass spectrometry (SIMS) or X-ray photoelectron spectroscopy (XPS). XPS is suitable when the content of the target element is high (e.g., 0.5 atomic% or more or 1 atomic% or more). On the other hand, SIMS is suitable when the content of the target element is low (e.g., less than 0.5 atomic% or less or 1 atomic% or less). When comparing elemental contents, it is more preferable to use a combined analysis of SIMS and XPS.

[0140] <First Organic Compound 161_1> As the first organic compound 161_1, an organic compound with electron transport properties is preferably used. Examples of such organic compounds include those with heteroaromatic rings. Furthermore, an organic compound with a π-electron-deficient heteroaromatic ring is more preferred, as this type of heteroaromatic ring is particularly electrochemically stable and possesses high electron transport properties. Additionally, in order for the first organic compound 161_1 to interact with the metal material 161_M and act as an electron donor for the second organic compound 161_2, the π-electron-deficient heteroaromatic ring preferably has a non-shared electron pair, which preferably exhibits electron-donating properties. That is, the first organic compound 161_1 preferably comprises a basic π-electron-deficient heteroaromatic ring. Furthermore, nitrogen has high electronegativity and therefore readily interacts with metals. Moreover, since nitrogen can form conjugated bonds in organic compounds, by incorporating nitrogen into the molecule, especially into the heteroaromatic ring, an organic compound with high carrier transport properties can be achieved. Therefore, the first organic compound 161_1 preferably has a heteroaromatic ring containing nitrogen. Note that the heteroaromatic ring is more preferably an even-numbered ring such as a six-membered or eight-membered ring. By employing this structure, the non-shared electron pairs on nitrogen are not involved in conjugation, thus facilitating interaction with the metallic material 161_M. Furthermore, in order to smoothly inject and transport electrons from the intermediate layer to the electron transport layer, the first organic compound 161_1 preferably possesses electron transport properties. Specifically, for example, the first organic compound 161_1 preferably has a pyridine ring.

[0141] Furthermore, the first organic compound 161_1 is preferably a material having two or more π-electron-deficient heteroaromatic rings bonded or fused together. Thus, when the metal material 161_M interacts with the first organic compound 161_1 and the second organic compound 161_2 using bidentate or polydentate ligands, it becomes stable, allowing the formation of an intermediate layer that is not easily degraded even after lithography processes involving atmospheric exposure. Therefore, even after lithography processes involving atmospheric exposure of the EL layer, electrons generated in the intermediate layer can be smoothly injected and transported to adjacent electron transport layers, thereby enabling the fabrication of a tandem light-emitting device with suppressed driving voltage rise, high luminous efficiency, and high reliability through lithography processes. Specifically, for example, the first organic compound 161_1 preferably has heteroaromatic rings comprising two or more pyridine rings. Organic compounds with a bipyridine skeleton are preferred because their nitrogen atoms readily coordinate with the metal, thus readily interacting with the metal material 161_M.

[0142] Furthermore, the phenanthroline ring is rigid and highly stable, making it a preferred choice. In particular, organic compounds containing the 1,10-phenanthroline ring in the phenanthroline ring have two nitrogen atoms that can coordinate with a metal, thus readily interacting with the metallic material 161_M, making them a preferred choice as well.

[0143] Furthermore, the first organic compound 161_1 may also have a structure in which multiple phenanthroline rings are linked by single bonds or by divalent groups. Specific examples of divalent groups include alkylene groups, arylene groups, etc.

[0144] An alkylene group is a divalent group formed by removing two hydrogen atoms from an alkane. Specific examples of alkylene groups include divalent groups that also have a structure formed by removing one hydrogen atom from the aforementioned alkyl groups.

[0145] An arylene is a divalent group formed by removing two hydrogen atoms from an aromatic hydrocarbon. As a specific example, a divalent group can be described that further removes one hydrogen atom from the aforementioned aryl group. Arylene groups can also have substituents; specific examples of such substituents include alkyl, alkoxy, and phenyl groups.

[0146] Furthermore, the first organic compound 161_1 preferably has an electron-donating substituent. Thus, the first organic compound 161_1 can possess high HOMO and high LUMO energy levels, thereby increasing the difference between the LUMO energy levels of the first organic compound 161_1 and the second organic compound 161_2. Moreover, the interaction between the metal material 161_M, the first organic compound 161_1, and the second organic compound 161_2 can further stabilize the composite material formed by this interaction, thereby forming an intermediate layer that is not easily degraded even after a process using lithography accompanied by atmospheric exposure. Therefore, even after a process using lithography accompanied by atmospheric exposure of the EL layer, electrons generated in the intermediate layer can be smoothly injected and transported to the adjacent electron transport layer. This allows for the fabrication of a tandem light-emitting device with suppressed driving voltage rise, high luminous efficiency, and high reliability through a lithography process.

[0147] In particular, organic compounds containing the 1,10-phenanthroline ring in a phenanthroline ring are preferred because the two nitrogen atoms in the phenanthroline ring can coordinate with the metal and thus readily interact with the metallic material 161_M.

[0148] Furthermore, as the first organic compound 161_1, an organic compound comprising a phenanthroline ring having an electron-donating group is more preferably used. In particular, by introducing an electron-donating group onto the 1,10-phenanthroline ring, the electron density of the phenanthroline ring can be increased, thereby improving the efficiency of interaction with the metallic material 161_M. Moreover, it is preferable that an electron-donating group is present at at least one of the 4 and 7 positions of the 1,10-phenanthroline ring. By introducing electron-donating groups at the 4 and 7 positions, the electron density of the nitrogen atoms at the 1 and 10 positions can be increased. Additionally, steric hindrance around the nitrogen atoms at the 1 and 10 positions can be avoided, and the electron density around them can be increased. Therefore, interaction with the metallic material 161_M can be facilitated, and this is preferred.

[0149] Furthermore, when the first organic compound 161_1 has a high basicity, it readily interacts with holes. Therefore, the hole transport in the first layer 161a using the first organic compound 161_1 can be significantly reduced. This prevents holes from transporting from the first layer 161a to the second layer 162a, resulting in a highly efficient light-emitting device, which is preferred. Specifically, the acidity coefficient pKa of the first organic compound 161_1 is preferably 8 or more, more preferably 10 or more, and even more preferably 12 or more.

[0150] Specific examples of electron-donating groups include alkyl, alkoxy, aryloxy, alkylamino, arylamino, and heterocyclic amino groups. However, the preferred electron-donating group introduced onto the phenanthroline ring is not limited to these. Any group that can increase the electron density of the phenanthroline ring can be used as an electron-donating group. Furthermore, the electron-donating group can also be introduced into the phenanthroline ring via an arylene group such as a p-phenylene group, which is preferably para-phenylene.

[0151] Alkyl groups represent hydrocarbons (C14- ... n H 2n+2 A monovalent group that removes one hydrogen atom. Specific examples of alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, isobutyl, tert-butyl, pentyl, isopentyl, sec-pentyl, tert-pentyl, neopentyl, hexyl, isohexyl, sec-hexyl, tert-hexyl, neohexyl, 3-methylpentyl, 2-methylpentyl, 2-ethylbutyl, 1,2-dimethylbutyl, 2,3-dimethylbutyl, etc.

[0152] An alkoxy group is a monovalent group having an alkyl group bonded to an oxygen atom. Specific examples of alkoxy groups include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, isobutoxy, tert-butoxy, n-pentoxy, isopentoxy, sec-pentoxy, tert-pentoxy, neopentoxy, n-hexoxy, isohexoxy, sec-hexoxy, tert-hexoxy, and neohexoxy.

[0153] An aryloxy group represents a monovalent group having an aryl group bonded to an oxygen atom. An aryl group represents a monovalent group formed by removing a hydrogen atom from one of the carbon atoms in a monocyclic or polycyclic aromatic compound. Specific examples of aryloxy groups include phenoxy, o-tolyloxy, m-tolyloxy, p-tolyloxy, mesityleneoxy, o-biphenyloxy, m-biphenyloxy, p-biphenyloxy, 1-naphthyloxy, 2-naphthyloxy, and 2-fluorenyloxy. Aryloxy groups can also have substituents; specific examples of such substituents include alkyl, alkoxy, and phenyl groups.

[0154] Alkylamino refers to a primary or secondary amine in which a hydrogen atom has been removed from the nitrogen atom by one or two alkyl groups bonded to the nitrogen atom. Specific examples of alkylamino include dimethylamino, diethylamino, etc.

[0155] Arylamino groups are monovalent groups formed by removing a hydrogen atom from the nitrogen atom of a primary or secondary amine, which has one or two aryl groups bonded to the nitrogen atom. Specific examples of arylamino groups include diphenylamino, bis(α-naphthyl)amino, and bis(m-tolyl)amino. Furthermore, arylamino groups can also have substituents; specific examples of such substituents include alkyl, alkoxy, and phenyl groups.

[0156] Furthermore, an amino group having both alkyl and aryl groups bonded to a nitrogen atom can be classified as either an alkylamino group or an arylamino group. Specific examples of such an amino group include N-methyl-N-phenylamino.

[0157] A heterocyclic amino group represents a monovalent group formed by removing a hydrogen atom from one of the nitrogen atoms in the ring of a heterocyclic amine. Note that here, heterocyclic amines refer to monocyclic or polycyclic heterocyclic compounds, and represent compounds in which at least one of the ring atoms is a nitrogen atom bonded with a hydrogen atom. Specific examples of heterocyclic amino groups include those represented by the following structural formulas (R-1) to (R-27). Note that heterocyclic amino groups may also have substituents; specific examples of such substituents include alkyl, alkoxy, and phenyl groups.

[0158] [Chemical Formula 3] Note that when the heterocyclic amino group is aromatic and the non-shared electron pair of the nitrogen atom contributes to the aromaticity, the electron-donating capacity of the phenanthrene ring is sometimes reduced compared to the case where the non-shared electron pair of the nitrogen atom does not contribute to the aromaticity. Therefore, among the aforementioned heterocyclic amino groups, it is more preferable to use heterocyclic amino groups where the non-shared electron pair of the nitrogen atom does not contribute to the aromaticity. Specifically, groups represented by structural formulas (R-1), (R-2), (R-3), (R-4), (R-5), (R-8), (R-9), (R-10), (R-12), (R-14), (R-15), (R-16), (R-17), (R-18), or (R-22) are more preferably electron-donating groups. Among these, groups represented by structural formulas (R-3), (R-4), (R-8), or (R-22) have high electron-donating capacity, which can further increase the electron density of the phenanthrene ring, and are therefore preferred.

[0159] Furthermore, as specific examples of electron-donating groups, groups represented by the following structural formulas (R-28) and (R-29) can be cited.

[0160] [Chemical Formula 4] Note that the organic compound containing a phenanthroline ring, which can be used as the first organic compound 161_1, can also have both the aforementioned electron-donating group and other substituents. Furthermore, when an electron-withdrawing group (cyano, fluorine, etc.) is introduced into the phenanthroline ring, the electron density of the phenanthroline ring sometimes decreases, making it less likely to interact with the metal material 161_M, so this is not preferred. Specific examples of substituents other than the aforementioned electron-donating group that can be introduced into the phenanthroline ring include aryl groups. Specific examples of aryl groups include phenyl, o-tolyl, m-tolyl, p-tolyl, mesitylene, o-biphenyl, m-biphenyl, p-biphenyl, 1-naphthyl, 2-naphthyl, 2-fluorenyl, etc. Aryl groups can also have substituents; specific examples of such substituents include alkyl, alkoxy, phenyl, etc.

[0161] Furthermore, the first organic compound 161_1 may also have a structure in which multiple phenanthroline rings are linked by single bonds or by divalent groups. Specific examples of divalent groups include alkylene groups, arylene groups, etc.

[0162] An alkylene group is a divalent group formed by removing two hydrogen atoms from an alkane. Specific examples of alkylene groups include divalent groups that also have a structure formed by removing one hydrogen atom from the aforementioned alkyl groups.

[0163] An arylene is a divalent group formed by removing two hydrogen atoms from an aromatic hydrocarbon. As a specific example, a divalent group can be described that further removes one hydrogen atom from the aforementioned aryl group. Arylene groups can also have substituents; specific examples of such substituents include alkyl, alkoxy, and phenyl groups.

[0164] Structural formulas (100) to (112) represent specific examples of organic compounds that can be used as the first organic compound 161_1. Note that the organic compounds that can be used as the first organic compound 161_1 are not limited thereto.

[0165] [Chemical Formula 5] Additionally, structural formula (100) represents Pyrrd-Phen, structural formula (101) represents 4,7-bis[4-(1-pyrrolyl)phenyl]-1,10-phenanthroline (abbreviated as: PrdP2Phen), structural formula (104) represents 4,7-bis(1,3,4,6,7,8-hexahydro-2H-pyrimidino[1,2-a]pyrimidin-1-yl)-1,10-phenanthroline (abbreviated as: 4,7hpp2Phen), structural formula (105) represents 4,7-bis(2,3,3a,4,5,6,7,7a-octahydro-1H-isoindol-2-yl)-1,10-phenanthroline (abbreviated as: Hid2Phen), and structural formula (107) represents 2 ,2'-(1,3-phenylene)bis[9-(1,3,4,6,7,8-hexahydro-2H-pyrimidino[1,2-a]pyrimidin-1-yl)-1,10-phenanthroline] (abbreviation: mhppPhen2P), structural formula (108) represents 2-(1,3,4,6,7,8-hexahydro-2H-pyrimidino[1,2-a]pyrimidin-1-yl)-9-phenyl-1,10-phenanthroline (abbreviation: 9Ph-2hppPhen), structural formula (109) represents 2,9-bis(1,3,4,6,7,8-hexahydro-2H-pyrimidino[1,2-a]pyrimidin-1-yl)-1,10-phenanthroline (abbreviation: 2,9hpp2Phen).

[0166] Furthermore, a smaller minimum ESP (i.e., a negative value with a large absolute value) for the first organic compound 161_1 improves the efficiency of its interaction with the metal material 161_M, which is preferred. In organic compounds with a phenanthroline ring, the ESP around the nitrogen atom of the phenanthroline ring tends to be negative, but by introducing an electron-donating group into the phenanthroline ring, the ESP around the nitrogen atom of the phenanthroline ring can be further reduced (increasing the absolute value of the negative value). Note that ESP refers to the interaction energy between a positive point charge with a unit charge and the electron distribution of the molecule. Furthermore, the value of ESP also varies depending on the threshold of electron density. To improve the efficiency of its interaction with the metal material 161_M, the minimum ESP of the first organic compound 161_1 is preferably smaller than the minimum ESP of the unsubstituent phenanthroline ring (larger in the negative direction). Specifically, when the threshold of electron density distribution in atomic units is 0.0004e / a0... 3 At this time, the minimum value of ESP is preferably -0.085E. h (E) h Hartley energy (1E) h =27.211eV or less, more preferably -0.090E h Below. Furthermore, when the threshold for electron density distribution is 0.003e / a0 3 At this time, the minimum value of ESP is preferably -0.12E. h Hereinafter, -0.13E is preferred. h the following.

[0167] <<Estimation of properties through quantum chemical calculations>> Minimum ESP values ​​of organic compounds represented by structural formulas (100) to (109) were estimated using quantum chemical calculations. Additionally, for comparison, minimum ESP values ​​of BPhen, mPPhen2P, NBPhen, and Phen were similarly estimated. The structural formulas of BPhen, mPPhen2P, NBPhen, and Phen are shown below.

[0168] [Chemical Formula 6] Gaussian09 was used as the quantum chemical calculation program. The calculations were performed using an SGI8600 from HPE. The most stable ground-state structure of the first organic compound, 161_1, was calculated using density functional theory (DFT). 6-311G(d,p) was used as the basis function, and B3LYP was used as the functional.

[0169] Table 6 shows the estimated minimum ESP values ​​for the first organic compound 161_1 in the ground state. Note that ESP refers to the interaction energy between a positive point charge of unit charge and the electron distribution of the molecule. Furthermore, the value of ESP varies depending on the threshold of electron density. Table 6 shows the density values ​​set to 0.0004e / a0 in atomic units. 3 Or 0.003e / a0 3 ESP of electron density distribution at time.

[0170] [Table 6] As shown in Table 6, among the organic compounds represented by structural formulas (100) to (105), the threshold for electron density distribution is 0.0004e / a0. 3 The minimum value of ESP is -0.085E. h Therefore, it is most suitable to use it as the first organic compound 161_1. On the other hand, it is known that the minimum ESP of the organic compounds represented by structural formulas (106) to (109) is greater than -0.085E. h .

[0171] It can be seen that the organic compounds represented by structural formulas (100) to (105) are organic compounds with electron-donating groups at the 4 and 7 positions of the 1,10-phenanthroline ring, and therefore have the most preferred values.

[0172] The organic compound represented by structural formula (106) is an organic compound with electron-donating groups at the 4 and 7 positions of the 1,10-phenanthroline ring, but the N-carbazo group is used as the electron-donating group. In the N-carbazo group, the non-shared electron pair of the nitrogen atom contributes to aromaticity, so compared with groups where the non-shared electron pair of the nitrogen atom does not contribute to aromaticity, the electron-donating ability of the phenanthroline ring is reduced, and therefore the minimum value of ESP does not easily decrease, thus yielding the above results.

[0173] The organic compounds represented by structural formulas (107) to (109) are organic compounds having electron-donating groups at positions 2 and 9 of the 1,10-phenanthroline ring. When electron-donating groups are introduced at positions 2 and 9 of the 1,10-phenanthroline ring, the co-donation of electrons to the nitrogen at positions 1 and 10 of the 1,10-phenanthroline ring is lower compared to when they are introduced at positions 4 and 7. Therefore, the preferred substitution positions for the electron-donating groups in the 1,10-phenanthroline ring are positions 4 and 7.

[0174] Furthermore, when the first organic compound 161_1 has a high basicity, it readily interacts with holes. Therefore, the hole transport in the first layer 161a using the first organic compound 161_1 can be significantly reduced. This prevents holes from transporting from the first layer 161a to the second layer 162a, resulting in a highly efficient light-emitting device, which is preferred. Specifically, the acidity coefficient pKa of the first organic compound 161_1 is preferably 8 or more, more preferably 10 or more, and even more preferably 12 or more.

[0175] In addition, when the acidity coefficient pKa of an organic compound is unknown, the acidity coefficient pKa of each skeleton of the organic compound can be investigated, and the largest acidity coefficient pKa can be regarded as the acidity coefficient pKa of the organic compound.

[0176] Alternatively, the acidity coefficient can be calculated. For example, the acidity coefficient pKa can be calculated using the following method.

[0177] The initial molecular structures of each molecule used in the computational model are the most stable structures (single ground state) obtained through first-principles calculations.

[0178] For the aforementioned first-principles calculations, the most stable structure in the singlet ground state was calculated using Jaguar, a quantum chemistry calculation software manufactured by Schrödinger, Inc., via density functional theory (DFT). 6-31G** was used as the basis function, and B3LYP-D3 was used as the functional. The structure used for the quantum chemistry calculations was sampled using Maestro GUI, also manufactured by Schrödinger, Inc., with conformational analysis performed using mixed torsional / low-mode sampling.

[0179] In pKa calculations, more than one atom in each molecule is designated as a basic position. The Macro Model is used to explore the stable structure of the protonated molecule in water, and the lowest-energy conformational isomers obtained through conformational exploration using the OPLS2005 force field are used. The structure is optimized using B3LYP / 6-31G* in Jaguar's pKa calculation module, followed by single-point calculations using cc-pVTZ(+), and pKa values ​​are calculated using empirical corrections for functional groups. For molecules where more than one atom is designated as a basic position, the largest value among the results is used as the pKa value. The obtained pKa values ​​are shown.

[0180] The acidity coefficient pKa of 2,9hpp2Phen is 13.35, that of 4,7hpp2Phen is 13.42, that of Pyrrd-Phen is 11.23, that of mPPhen2P is 5.16, that of NBPhen is 5.59, and that of BPhen is 5.62.

[0181] <Second Organic Compound 161_2> As the second organic compound 161_2, an organic compound with electron transport properties is preferably used. As an organic compound with electron transport properties, it is preferable to use one with an electron mobility of 1×10⁻⁶ when the square root of the electric field strength [V / cm] is 600. -7 cm 2 For substances with an electron mobility of 1×10⁶ / Vs or higher, it is preferable to use a substance with an electron mobility of 1×10⁶ / Vs. -6 cm 2 Substances with a value of / Vs or higher. Furthermore, any substance other than those mentioned above can be used as long as its electron transport capacity is higher than its hole transport capacity.

[0182] Furthermore, as an organic compound with electron transport properties, an organic compound having a π-electron-deficient heteroaromatic ring is preferred. As a π-electron-deficient heteroaromatic ring, heteroaromatic rings with an azole skeleton (imidazolium ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadiazole ring, thiadiazole ring), heteroaromatic rings with a pyridine skeleton, heteroaromatic rings with a diazine skeleton, and heteroaromatic rings with a triazine skeleton are preferred. Among these, diazine rings (pyrazine rings, pyrimidine rings, pyridazine rings) or triazine rings are electrochemically stable and have high electron transport properties, and are therefore preferred.

[0183] As an example of an organic compound that can be used as the second organic compound 161_2, an organic compound represented by the following general formula (G1-1) can be cited.

[0184] [Chemical Formula 7] In the above general formula (G1-1), A 1 A 2 and A 3 A represents a heteroaryl ring with 1 or more but less than 30 substituted or unsubstituted carbon atoms, respectively. 1 A 2 and A 3 They can also form fused rings with each other.

[0185] Organic compounds represented by the general formula (G1-1) have conjugated double bonds formed by the N atoms on each heteroaromatic ring arranged in the order NCCN, and possess the function of interacting with metals as tridentate or higher ligands. Organic compounds with this structure readily interact with metals, and therefore can be applied to the second organic compound 161_2.

[0186] In the above general formula (G1-1), as a result of A 1 A 2 and A 3 This refers to heteroaromatic rings with 1 or more but less than 30 substituted or unsubstituted carbon atoms. Examples include heteroaromatic rings with a pyridine skeleton (pyridine ring, quinoline ring, isoquinoline ring, naphthidine ring, bipyridine ring, phenanthridine ring, phenanthroxolin ring, anthridine ring, aziridine ring), heteroaromatic rings with a diazine skeleton (pyrazine ring, pyrimidine ring, pyridazine ring, quinoxolin ring, benzoquinoxolin ring, dibenzoquinoxolin ring, quinazoline ring, benzoquinoxolin ring, phthalazine ring, borazine ring, pteridine ring, phenazine ring), heteroaromatic rings with a triazine skeleton, and heteroaromatic rings with an azole skeleton (imidazolium ring, benzimidazole ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadiazole ring, thiadiazole ring), etc. Note that A... 1 A 2 and A 3 The heteroaromatic rings represented by substituted or unsubstituted carbon atoms having 1 or more but less than 30 are not limited to this. A 1 A 2 and A 3 They can also form fused rings. For example, A 1 With A 2 They can also bond together to form phenanthrene-rhein rings.

[0187] Furthermore, as an example of an organic compound that can be used as the second organic compound 161_2, an organic compound represented by the following general formula (G2-1) can be cited.

[0188] [Chemical Formula 8] In the general formula (G2-1), X 1 To X 6 Each of these groups independently represents carbon (C) or nitrogen (N), and carbon (C) is bonded to hydrogen, an alkyl group with 1 or more but less than 10 carbon atoms, a cycloalkyl group with 3 or more but less than 10 substituted or unsubstituted carbon atoms, an aryl group with 6 or more but less than 30 substituted or unsubstituted carbon atoms, or a heteroaryl group with 1 or more but less than 30 substituted or unsubstituted carbon atoms. R 1 To R 4Each of the following can be independently represented: hydrogen, an alkyl group with 1 or more but less than 10 carbon atoms, a cycloalkyl group with 3 or more but less than 10 substituted or unsubstituted carbon atoms, an aryl group with 6 or more but less than 30 substituted or unsubstituted carbon atoms, or a heteroaryl group with 1 or more but less than 30 substituted or unsubstituted carbon atoms. Alternatively, in general formula (G2-1), X 1 To X 6 They can also form fused rings by direct bonding or by bonding through divalent groups. Specific examples of divalent groups include alkylene groups and arylene groups.

[0189] As with organic compounds represented by general formula (G2-1), organic compounds that function as tridentate or higher ligands interacting with metals more preferably include at least one of heteroaromatic rings having a pyridine skeleton, a diazine skeleton, and a triazine skeleton. These rings exhibit excellent electrochemical stability, thus providing a reliable light-emitting device. Furthermore, due to their excellent electron transport properties, a light-emitting device with a reduced driving voltage can be provided.

[0190] Furthermore, as an example of an organic compound that can be used as the second organic compound 161_2, an organic compound represented by the following general formula (G3-1) can be cited.

[0191] [Chemical Formula 9] In general formula (G3-1), X 1 To X 4 Each of these groups independently represents carbon (C) or nitrogen (N), and carbon (C) is bonded to hydrogen, an alkyl group with 1 or more but less than 10 carbon atoms, a cycloalkyl group with 3 or more but less than 10 substituted or unsubstituted carbon atoms, an aryl group with 6 or more but less than 30 substituted or unsubstituted carbon atoms, or a heteroaryl group with 1 or more but less than 30 substituted or unsubstituted carbon atoms. R 1 To R 6 Each of the following can be independently represented: hydrogen, alkyl with 1 or more and 10 or less carbon atoms, cycloalkyl with 3 or more and 10 or less substituted or unsubstituted carbon atoms, aryl with 6 or more and 30 or less substituted or unsubstituted carbon atoms, or heteroaryl with 1 or more and 30 or less substituted or unsubstituted carbon atoms.

[0192] Furthermore, as an example of an organic compound that can be used as the second organic compound 161_2, an organic compound represented by the following general formula (G4-1) can be cited.

[0193] [Chemical Formula 10] In the general formula (G4-1), X 1 To X5 Each of these groups independently represents carbon (C) or nitrogen (N), and carbon (C) is bonded to hydrogen, an alkyl group with 1 or more but less than 10 carbon atoms, a cycloalkyl group with 3 or more but less than 10 substituted or unsubstituted carbon atoms, an aryl group with 6 or more but less than 30 substituted or unsubstituted carbon atoms, or a heteroaryl group with 1 or more but less than 30 substituted or unsubstituted carbon atoms. R 1 To R 6 Each of the following can be independently represented: hydrogen, alkyl with 1 or more and 10 or less carbon atoms, cycloalkyl with 3 or more and 10 or less substituted or unsubstituted carbon atoms, aryl with 6 or more and 30 or less substituted or unsubstituted carbon atoms, or heteroaryl with 1 or more and 30 or less substituted or unsubstituted carbon atoms.

[0194] Organic compounds with a pyridine skeleton are preferred due to their high LUMO energy level. For example, when X in general formulas (G2-1), (G3-1), and (G4-1)... 1 and X 2 When carbon is represented, this organic compound has a high LUMO energy level due to its pyridine framework, and therefore can form a composite material with a high SOMO energy level when interacting with a metal. In other words, an organic compound with a pyridine ring and the ability to interact as a tripentate or higher ligand can form an intermediate layer with high electron injection capability through interaction with a metal.

[0195] Furthermore, organic compounds with diazine or triazine skeletons are preferred due to their electrochemical stability and high electron transport properties. For example, when X in general formulas (G2-1), (G3-1), and (G4-1) 1 and X 2 When at least one of the elements represents nitrogen, the organic compound is electrochemically stable and has high electron transport due to its diazine or triazine skeleton, thus enabling it to form a stable and highly electron-transportable composite material when interacting with a metal. In other words, an organic compound having a diazine or triazine ring and functioning as a tridentate or higher ligand can form a highly reliable intermediate layer through interaction with a metal.

[0196] Furthermore, as an example of an organic compound that can be used as the second organic compound 161_2, an organic compound represented by the following general formula (G1-2) can be cited.

[0197] [Chemical Formula 11] In the above general formula (G1-2), A 1 and A 2 A represents a heteroaryl ring with 1 or more but less than 30 substituted or unsubstituted carbon atoms, respectively. 1 and A2 They can also form fused rings, A 1 It includes two or more nitrogen atoms.

[0198] Organic compounds represented by the general formula (G1-2) have conjugated double bonds formed by the N atoms on the heteroaromatic ring arranged in the order NCCN, and possess the function of interacting with metals as bidentate or higher ligands. Organic compounds with this structure readily interact with metals, and therefore can be used in the intermediate layer.

[0199] In the above general formula (G1-2), as a result of A 1 The term refers to heteroaromatic rings with 1 or more but less than 30 substituted or unsubstituted carbon atoms. Examples include heteroaromatic rings with a diazine skeleton (pyrazine, pyrimidine, pyridazine, quinoxaline, benzoquinoxaline, dibenzoquinoxaline, quinazoline, benzoquinazoline, phthalazine, borazine, pteridine, phenazine), heteroaromatic rings with a triazine skeleton, and heteroaromatic rings with an azole skeleton (imidazolium, benzimidazole, pyrazole, oxazole, thiazole, triazole, oxadiazole, thiadiazole). As a heteroaromatic ring composed of A... 2 This refers to heteroaromatic rings with 1 or more but less than 30 substituted or unsubstituted carbon atoms. Examples include heteroaromatic rings with a pyridine skeleton (pyridine ring, quinoline ring, isoquinoline ring, naphthidine ring, bipyridine ring, phenanthridine ring, phenanthroxolin ring, anthridine ring, azafluoranthracene ring), heteroaromatic rings with a diazine skeleton (pyrazine ring, pyrimidine ring, pyridazine ring, quinoxolin ring, benzoquinoxolin ring, dibenzoquinoxolin ring, quinazoline ring, benzoquinoxolin ring, phthalazine ring, borazine ring, pteridine ring, phenazine ring), heteroaromatic rings with a triazine skeleton, and heteroaromatic rings with an azole skeleton (imidazolium ring, benzimidazole ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadiazole ring, thiadiazole ring), etc. Note that A... 1 and A 2 The heteroaromatic rings represented by substituted or unsubstituted carbon atoms having 1 or more but less than 30 are not limited to this. A 1 and A 2 They can also form fused rings. For example, A 1 With A 2 They can also bond with each other to form a pyrazine-quinoxaline ring.

[0200] Furthermore, as an example of an organic compound that can be used as the second organic compound 161_2, an organic compound represented by the following general formula (G2-2) can be cited.

[0201] [Chemical Formula 12] In the general formula (G2-2), X 1 To X 4At least one of them represents nitrogen (N), and the others independently represent carbon (C) or nitrogen (N), wherein carbon (C) is bonded to hydrogen, an alkyl group having 1 or more but less than 10 carbon atoms, a cycloalkyl group having 3 or more but less than 10 substituted or unsubstituted carbon atoms, an aryl group having 6 or more but less than 30 substituted or unsubstituted carbon atoms, or a heteroaryl group having 1 or more but less than 30 substituted or unsubstituted carbon atoms, R 1 To R 4 Each of the following can be independently represented: hydrogen, an alkyl group with 1 or more but less than 10 carbon atoms, a cycloalkyl group with 3 or more but less than 10 substituted or unsubstituted carbon atoms, an aryl group with 6 or more but less than 30 substituted or unsubstituted carbon atoms, or a heteroaryl group with 1 or more but less than 30 substituted or unsubstituted carbon atoms. Alternatively, in general formula (G2-2), X 1 To X 4 They can also form fused rings by direct bonding or by bonding through divalent groups. Specific examples of divalent groups include alkylene groups and arylene groups.

[0202] Organic compounds represented by the general formula (G2-2), such as those functioning as bidentate or higher ligands interacting with metals, more preferably include heteroaromatic rings with a diazine skeleton or a triazine skeleton. These rings exhibit excellent electrochemical stability, thus providing a reliable light-emitting device. Furthermore, due to their excellent electron transport properties, a light-emitting device with a reduced driving voltage can be provided.

[0203] Furthermore, as an example of an organic compound that can be used as the second organic compound 161_2, an organic compound represented by the following general formula (G3-2) can be cited.

[0204] [Chemical Formula 13] In the general formula (G3-2), X 1 and X 2 One of them represents nitrogen (N), and the other represents carbon (C) or nitrogen (N). The carbon (C) is bonded to hydrogen, an alkyl group with 1 or more but less than 10 carbon atoms, a cycloalkyl group with 3 or more but less than 10 substituted or unsubstituted carbon atoms, an aryl group with 6 or more but less than 30 substituted or unsubstituted carbon atoms, or a heteroaryl group with 1 or more but less than 30 substituted or unsubstituted carbon atoms. R 1 To R 6 Each of the following can be independently represented: hydrogen, alkyl with 1 or more and 10 or less carbon atoms, cycloalkyl with 3 or more and 10 or less substituted or unsubstituted carbon atoms, aryl with 6 or more and 30 or less substituted or unsubstituted carbon atoms, or heteroaryl with 1 or more and 30 or less substituted or unsubstituted carbon atoms.

[0205] Furthermore, as an example of an organic compound that can be used as the second organic compound 161_2, an organic compound represented by the following general formula (G4-2) can be cited.

[0206] [Chemical Formula 14] In the general formula (G4-2), X 1 To X 3 At least one of them represents nitrogen (N), and the others independently represent carbon (C) or nitrogen (N), wherein carbon (C) is bonded to hydrogen, an alkyl group having 1 or more but less than 10 carbon atoms, a cycloalkyl group having 3 or more but less than 10 substituted or unsubstituted carbon atoms, an aryl group having 6 or more but less than 30 substituted or unsubstituted carbon atoms, or a heteroaryl group having 1 or more but less than 30 substituted or unsubstituted carbon atoms, R 1 To R 5 Each of the following can be independently represented: hydrogen, alkyl with 1 or more and 10 or less carbon atoms, cycloalkyl with 3 or more and 10 or less substituted or unsubstituted carbon atoms, aryl with 6 or more and 30 or less substituted or unsubstituted carbon atoms, or heteroaryl with 1 or more and 30 or less substituted or unsubstituted carbon atoms.

[0207] Organic compounds with a pyridine skeleton are preferred due to their high LUMO energy level. For example, when X in general formulas (G2-2) and (G4-2) 1 and X 2 and X in general formula (G3-2) 1 When carbon is represented, this organic compound has a high LUMO energy level due to its pyridine framework, and therefore can form a composite material with a high SOMO energy level when interacting with a metal. In other words, an organic compound with a pyridine ring and the ability to interact as a bidentate or higher ligand can form an intermediate layer with high electron injection capability through interaction with a metal.

[0208] Furthermore, organic compounds with diazine or triazine skeletons are preferred due to their electrochemical stability and high electron transport properties. For example, when X in general formulas (G2-2) and (G4-2) 1 and X 2 At least one of them and X in general formula (G3-2) 1 When nitrogen is represented, the organic compound is electrochemically stable and has high electron transport due to its diazine or triazine skeleton. Therefore, it can form a stable composite material with high electron transport when interacting with a metal. In other words, organic compounds with diazine or triazine rings and the ability to act as bidentate or higher ligands can form a highly reliable intermediate layer through interaction with a metal.

[0209] The following examples of organic compounds that can be used as the second organic compound 161_2 are shown by general formulas (250) to (268) and more specific examples of organic compounds represented by the above general formulas (G1-1) to (G4-2).

[0210] [Chemical Formula 15] [Chemical Formula 16] In general formulas (250) to (268), R 11 To R 162 Each of the following can be independently represented: hydrogen, alkyl group having 1 or more but less than 10 carbon atoms, cycloalkyl group having 3 or more but less than 10 substituted or unsubstituted carbon atoms, aryl group having 6 or more but less than 30 substituted or unsubstituted carbon atoms, or heteroaryl group having 1 or more but less than 30 substituted or unsubstituted carbon atoms.

[0211] Furthermore, examples of substituents that can be used in the above general formulas (G1-1) to (G4-2) and general formulas (250) to (268) include alkyl groups with 1 or more but less than 10 carbon atoms, cycloalkyl groups with 3 or more but less than 10 carbon atoms, aryl groups with 6 or more but less than 30 carbon atoms, arylene groups with 6 or more but less than 30 carbon atoms, and heteroaryl groups with 1 or more but less than 30 carbon atoms. Note that some or all of the hydrogen atoms may also be deuterium. Additionally, the groups that can be used in the above general formulas are not limited to the specific examples below.

[0212] Specific examples of alkyl groups having 1 or more but less than 10 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, isobutyl, tert-butyl, pentyl, isopentyl, sec-pentyl, tert-pentyl, neopentyl, hexyl, isohexyl, sec-hexyl, tert-hexyl, neohexyl, 3-methylpentyl, 2-methylpentyl, 2-ethylbutyl, 1,2-dimethylbutyl, 2,3-dimethylbutyl, 1-ethylhexyl, etc.

[0213] Specific examples of cycloalkyl groups with 3 or more but less than 10 carbon atoms include cyclopropyl, cyclobutyl, methylcyclobutyl, cyclopentyl, methylcyclopentyl, isopropylcyclopentyl, tert-butylcyclopropyl, cyclohexyl, methylcyclohexyl, isopropylcyclohexyl, tert-butylcyclohexyl, cycloheptyl, methylcycloheptyl, isopropylcycloheptyl, cyclooctyl, methylcyclooctyl, isopropylcyclohexyl, cyclononyl, methylcyclononyl, cyclodecyl, adamantyl, etc.

[0214] Specific examples of aryl groups with 6 or more but less than 30 carbon atoms include phenyl, o-tolyl, m-tolyl, p-tolyl, mesitylelel, o-biphenyl, m-biphenyl, p-biphenyl, 1-naphthyl, 2-naphthyl, fluorenyl, 9,9-dimethylfluorenyl, spirodifluorenyl, phenanthryl, anthracenel, and fluoranthyl. When an aryl group with 6 or more but less than 30 carbon atoms has a substituent, examples of such substituents include alkyl groups with 1 or more but less than 10 carbon atoms, cycloalkyl groups with 3 or more but less than 10 carbon atoms, and phenyl groups.

[0215] Specific examples of arylene groups with 6 or more but less than 30 carbon atoms include phenylene, biphenyl-diyl, naphthyl-diyl, fluorene-diyl, acenaphthene-diyl, anthracene-diyl, phenanthrene-diyl, terphenyl-diyl, triphenylene-diyl, phenanthrene-diyl, tetraphenyl, benzanthracene-diyl, pyrene-diyl, and spirobis[9H-fluorene]-diyl. When the arylene group with 6 or more but less than 30 carbon atoms has a substituent, examples of such substituents include alkyl groups with 1 or more but less than 10 carbon atoms, cycloalkyl groups with 3 or more but less than 10 carbon atoms, and phenyl groups.

[0216] A heteroaryl group having 1 or more but less than 30 carbon atoms refers to a monovalent group formed by removing one hydrogen atom from one of the carbon atoms in a monocyclic or polycyclic heterocyclic aromatic compound having 1 or more but less than 30 carbon atoms. Specific examples of heteroaryl groups having 1 or more but less than 30 carbon atoms include 1,3,5-triazin-2-yl, 1,2,4-triazin-3-yl, pyrimidin-4-yl, pyrazin-2-yl, 2-pyridinyl, 3-pyridinyl, 4-pyridinyl, carbazole, dibenzofuranyl, dibenzothiopheneyl, benzonaphthofuranyl, benzonaphthothiopheneyl, indolocarbazoleyl, benzofuranocarbazoleyl, benzothiophenocarbazoleyl, indocarbazoleyl, dibenzocarbazoleyl, etc. When the heteroaryl group has a substituent, examples of such substituents include alkyl groups having 1 or more but less than 10 carbon atoms, cycloalkyl groups having 3 or more but less than 10 carbon atoms, and phenyl groups.

[0217] The following shows specific examples of organic compounds that can be used as the second organic compound 161_2 and organic compounds represented by the above general formulas (G1-1) to (G4-2).

[0218] [Chemical Formula 17] [Chemical Formula 18] [Chemical Formula 19] The organic compound that can be used as the second organic compound 161_2 is not limited to the above-mentioned organic compounds. An organic compound that has electron transport properties and forms an excitocomplex with the first organic compound 161_1 can be used as the second organic compound 161_2.

[0219] As organic compounds with electron transport capabilities, examples include 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviated as PBD), 3-(4-biphenyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviated as TAZ), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene (abbreviated as OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazole-2-yl)phenyl]-9H-carbazole (abbreviated as CO11), 2,2',2''-(1,3,5-phenyltriyl)tris(1-phenyl-1H-benzimidazole) (abbreviated as TPBI), and 2-[3-(diphenyltriyl)benzene... Organic compounds with an azole skeleton, such as 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviated as mDBTBIm-II), 3,5-bis[3-(9H-carbazole-9-yl)phenyl]pyridine (abbreviated as 35DCzPPy), 1,3,5-tris[3-(3-pyridine)phenyl]benzene (abbreviated as TmPyPB), phenanthroline (abbreviated as BPhen), copper bath (abbreviated as BCP), NBPhen, mPPhen2P, 4,7-diphenyl-2,9-bis(4-(1-phenyl-1H-benzimidazol-2-yl)phenyl)-1,10-phenanthroline (… Organic compounds containing heteroaromatic rings with a pyridine skeleton, such as DBimiBphen, 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-{3-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviation: 2mPCCzPDBq) ), 2-[4'-(9-phenyl-9H-carbazole-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mpPCBPDBq), 2-[4-(3,6-diphenyl-9H-carbazole-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II) and 6-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 9-[3'-(dibenzothiophene-4-yl)biphenyl-3-yl]naphtho[1',2':4,5] Furano[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), 9-[3'-(dibenzothiophene-4-yl)biphenyl-4-yl]naphtho[1',2':4,5]furano[2,3-b]pyrazine (abbreviation: 9pmDBtBPNfpr), 4,6-bis[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3- [Dibenzothiophene-4-yl]phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazole-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 9,9'-[pyrimidine-4,6-diylbis(biphenyl-3,3'-diyl)]bis(9H-carbazole) (abbreviation: 4,6mCzBP2Pm), 8-(biphenyl-4-yl)-4- [3-(dibenzothiophene-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 8-(p-triphenyl-3-yl)-4-[3-(dibenzothiophene-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (abbreviation: 8mpTP-4mDBtPBfpm), 8-([1,1':4',1'') -triphenyl-2,4,5,6,2',3',5',6',2'',3'',4'',5'',6''-d13]-3-yl)-4-{3-[(dibenzothiophene-1,2,3,6,7,8,9-d7)-4-yl]phenyl-2,4,6-d3}-[1]benzofurano[3,2-d]pyrimidine (abbreviation: 8mpTP-4mDBtPBfpm-d, 23), 3,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzofuran[2,3-b]pyrazine (abbreviation: 3,8mDBtP2Bfpr), 4,8-bis[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuran[3,2-d]pyrimidine (abbreviation: 4,8mDBtP2Bfpm), 8-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furan[3,2-d]pyrimidine (abbreviation: 8mDBtBPNfpm), 8-([2,2'-binaphthyl]-6-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuran[3,2-d]pyrimidine (abbreviation: 8(βN2) -4mDBtPBfpm), 6-(biphenyl-3-yl)-4-[3,5-bis(9H-carbazole-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2PPm), 2,6-bis(4-naphth-1-ylphenyl)-4-[4-(3-pyridine)phenyl]pyrimidine (abbreviation: 2,4NP-6PyPPm), 4-[3,5-bis(9H-carbazole-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine (abbreviation: 6BP-4Cz2PPm), 7-[4-(9-phenyl-9H-carbazole-2-yl)quinazolin-2-yl]-7H-dibenzo[c,g]carbazole (abbreviation: PC-cgDBCzQz), etc., which have a diazine skeleton, are among the following. Organic compounds, 2-(biphenyl-4-yl)-4-phenyl-6-(9,9'-spirobis[9H-fluorene]-2-yl)-1,3,5-triazine (abbreviation: BP-SFTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-8-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-6-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn-02), 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-biphenyl-4-yl)phenyl-4-phenyl-6 ... -9H-carbazole (abbreviation: mPCCzPTzn-02), 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mFBPTzn), 5-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-7,7-dimethyl-5H,7H-indo[2,1-b]carbazole (abbreviation: mINc(II)PTzn), 2-{3-[3-(dibenzothiophene-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mDBtBPTzn), 2,4,6-tris[3'-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-Triazine (abbreviation: TmPPPyTz), 2-[3-(2,6-dimethyl-3-pyridyl)-5-(9-phenanthyl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTzn), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazin-2-yl]-11,12-dihydro-12-phenylindolo[2,3-a]carbazole (abbreviation: BP-Icz(II)Tzn), 2-[3'-(triphenyl-2-yl)biphenyl-3-yl] Organic compounds with a triazine skeleton include 3-[9-(4,6-diphenyl-1,3,5-triazine-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (PCDBfTzn), 2-(biphenyl-3-yl)-4-phenyl-6-[8-([1,1':4',1''-terphenyl]-4-yl)-1-dibenzofuranyl]-1,3,5-triazine (mBP-TPDBfTzn).

[0220] Among the aforementioned organic compounds, those with phenanthrene-rhein rings, such as BPhen, BCP, NBPhen, and mPPhen2P, are more preferred, especially those with 1,10-phenanthrene-rhein rings, because the two nitrogen atoms contained therein can coordinate with metals, thus facilitating interaction with metals. Furthermore, organic compounds with phenanthrene-rhein ring dimer structures, such as mPPhen2P, exhibit high stability and are therefore even more preferred.

[0221] Furthermore, the organic compound that can be used as the second organic compound 161_2 preferably has 25 or more and 100 or less carbon atoms. When it has the above number of carbon atoms, an organic compound with good sublimation properties can be obtained, thereby suppressing the thermal decomposition of the organic compound during vacuum evaporation and thus obtaining good material utilization efficiency. In addition, the glass transition temperature (T) can also be used. g The organic compound is heated to temperatures above 100°C. This makes the intermediate layer less prone to crystallization. Therefore, when processing a portion of the organic compound layer using lithography, a layer that is not easily crystallized even by atmospheric oxygen or water, or by the chemicals or water used in the process, can be formed. This prevents an increase in driving voltage or a decrease in current efficiency of the light-emitting device due to crystallization of the intermediate layer. Therefore, by using T... g An organic compound with a temperature above 100°C is used as the second organic compound 161_2, which can be used as the intermediate layer of a light-emitting device processed by lithography on a portion of the organic compound layer.

[0222] As having a phenanthroline ring and its T gFor organic compounds that are heated above 100°C, NBPhen (T) can be cited as an example. g :165℃), mPPhen2P (T g : 135℃), 2,2'-(biphenyl-4,4'-diyl)bis(9-phenyl-1,10-phenanthroline) (abbreviation: PPhen2BP) (T g : 166℃), 2,2'-biphenyl-3,3'-dimethylbis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2BP) (T g :144℃), 2,8-bis(phenanthroline-5-yl)dibenzofuran (abbreviation: 2,8Phen2DBf) (T g : 210℃), 5,5',5''-(benzene-1,3,5-triyl)tri-1,10-phenanthroline (abbreviation: Phen3P) (T g (e.g., 257℃). For example, using a differential scanning calorimeter (DSC8500 manufactured by PerkinElmer, Japan Co., Ltd.), the powder is placed on an aluminum unit and heated at 40℃ / min, thereby allowing the measurement of T. g .

[0223] Furthermore, as the second organic compound 161_2, an organic compound with an acidity coefficient pKa of 4 or higher and lower than 8 can be used. This reduces the hole transport properties of the second organic compound 161_2, thereby reducing the hole transport properties of the first layer 161a in the intermediate layer 160a. This prevents holes from transporting from the first layer 161a to the second layer 162a, resulting in a highly efficient light-emitting device, which is therefore preferred. However, when the acidity coefficient pKa is too high, water solubility increases, sometimes reducing the resistance to water and chemicals used in the lithography process. Therefore, the acidity coefficient pKa of the second organic compound 161_2 is preferably 4 or higher and lower than 8.

[0224] Layers containing a combination of metallic material 161_M, a first organic compound 161_1, and a second organic compound 161_2 exhibit more efficient material interactions compared to layers containing only two of these materials (e.g., layers containing metallic material 161_M and the first organic compound 161_1, or layers containing metallic material 161_M and the second organic compound 161_2). This can be demonstrated by incorporating odd-group metals into metallic material 161_M and measuring the spin density of the films containing each material using electron spin resonance (ESR).

[0225] For example, preferably, the spin density of the film containing the metal, the first organic compound 161_1, and the second organic compound 161_2, as measured by ESR, is higher than the spin density of the film containing the metal and the first organic compound 161_1, or the spin density of the film containing the metal and the second organic compound 161_2, as measured by ESR. In this case, it can be confirmed that the material interactions in the layer containing the combination of the metal, the first organic compound 161_1, and the second organic compound 161_2 are generated more efficiently than in a layer containing only two of these materials. Furthermore, it is preferable to perform the spin density measurement using electron spin resonance at room temperature.

[0226] More specifically, the mixed film comprising the metal and the first organic compound 161_1 arises from the spin density of a signal observed, for example, near a g-value of 2.00, using electron spin resonance. 16 spins / cm 3 The following mixed film, containing a metal and a second organic compound 161_2, is derived from a signal with a spin density of 2 × 10⁻⁶ observed, for example, near a g-value of 2.00, using electron spin resonance. 16 spins / cm 3 The following mixture of organic compound 161_1 and organic compound 161_2 is derived from the electron spin resonance method, for example, the spin density of the signal observed near a g value of 2.00 is 2 × 10⁻⁶. 16 spins / cm 3 In the following cases, when the mixed film containing the metal, the first organic compound 161_1, and the second organic compound 161_2 is caused by a signal with a spin density of 5 × 10⁻⁶ observed, for example, near a g value of 2.00, using the electron spin resonance method. 16 spins / cm 3 The above, and more preferably 1×10 17 spins / cm 3 In the above, it can be confirmed that the materials interact more efficiently in a layer containing a combination of metal, first organic compound 161_1 and second organic compound 161_2 compared to a layer containing only two of the materials in the above combination.

[0227] Furthermore, regarding the ratio of the metal, it is preferable that its molar ratio relative to the sum of the first organic compound 161_1 and the second organic compound 161_2 is 0.1 or more and 10 or less, more preferably 0.2 or more and 5 or less, and even more preferably 0.5 or more and 2 or less. Alternatively, the volume ratio is preferably 0.005 or more and 0.3 or less, more preferably 0.01 or more and 0.1 or less, and even more preferably 0.01 or more and 0.05 or less. By mixing the metal, the first organic compound 161_1, and the second organic compound 161_2 in the above ratio, an intermediate layer with good electron injection properties can be provided. Furthermore, regarding the ratio of the first organic compound 161_1, it is preferable that its volume ratio relative to the second organic compound 161_2 is 0.1 or more and 10 or less, more preferably 0.2 or more and 5 or less, and even more preferably 0.5 or more and 2 or less. By mixing the first organic compound 161_1 and the second organic compound 161_2 in the above ratio, an intermediate layer with good electron transport properties can be provided.

[0228] Furthermore, the thickness of the first layer 161a located on the anode side of the intermediate layer 160a is preferably 3 nm or more and 20 nm or less, more preferably 5 nm or more and 10 nm or less. This allows the composite material formed by mixing the metal, the first organic compound 161_1, and the second organic compound 161_2 to function effectively, providing a light-emitting device with good luminous efficiency.

[0229] Next, the preferred structures of the second and third layers when layer 200 is used as the first layer in the intermediate layer will be described.

[0230] [Second Layer] As the second layer in the intermediate layer, it is preferable to use a layer containing a third organic compound and a fourth organic compound. This allows for good hole injection into the upper light-emitting layer, making it a preferred option.

[0231] <Third Organic Compound> The third organic compound is preferably an organic compound with hole-transporting properties. Various organic compounds can be used as hole-transporting organic compounds, such as aromatic amines, heteroaromatic compounds, aromatic hydrocarbons, and polymers (oligomers, dendritic polymers, polymers, etc.). Preferably, the organic compound with a hole mobility of 1×10⁻⁶ is used. -6 cm 2Organic compounds with a ratio of / Vs or higher. Organic compounds with hole-transporting capabilities are preferably compounds containing fused aromatic rings or π-electron-rich heteroaromatic rings. As fused aromatic rings, anthracene rings, naphthalene rings, etc., are preferred. Furthermore, as π-electron-rich heteroaromatic rings, fused aromatic rings having at least one of a pyrrole skeleton, a furan skeleton, and a thiophene skeleton are preferred, specifically carbazole rings, dibenzothiophene rings, or rings where these rings are also fused with aromatic or heteroaromatic rings.

[0232] Such hole-transporting organic compounds more preferably have at least one of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton. In particular, they can also be aromatic amines having substituents including a dibenzofuran ring or a dibenzothiophene ring, aromatic monoamines including a naphthyl ring, or aromatic monoamines in which a 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group. Note that when these hole-transporting organic compounds are substances including N,N-bis(4-biphenyl)amino groups, long-lifetime light-emitting devices can be manufactured, and therefore they are preferred.

[0233] Specifically, examples of the aforementioned hole-transporting organic compounds include N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviated as: BnfABP), N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviated as: BBABnf), 4,4'-bis(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl)-4''-phenyltriphenylamine (abbreviated as: BnfBB1BP), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-6-amine (abbreviated as: BBABnf(6)), and N,N-bis(4-biphenyl)benzo[b]naphtho[1,2- d]furan-8-amine (abbreviation: BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan-4-amine (abbreviation: BBABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), N-[4-(dibenzothiophen-4-yl)phenyl]-N-phenyl-4-benzidine (abbreviation: ThBA1BP), 4-(2-naphthyl)-4',4''-diphenyltriphenylamine (abbreviation: BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4''-diphenyltriphenylamine (abbreviation: BBAβNBi), 4,4'-diphenyl-4' 4,4'-diphenyl-4''-([2,1'-binathyl]-6-yl)triphenylamine (abbreviation: BBAαNβNB), 4,4'-diphenyl-4''-([2,1'-binathyl]-7-yl)triphenylamine (abbreviation: BBAαNβNB-03), 4,4'-diphenyl-4''-(7-phenyl)naphthyl-2-yltriphenylamine (abbreviation: BBAPβNB-03), 4,4'-diphenyl-4''-([2,2'-binathyl]-6-yl)triphenylamine (abbreviation: BBA(βN2)B), 4,4'-diphenyl-4''-([2,2'-binathyl]-7-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4,4'-diphenyl-4''-([1,2'-binathyl]-6-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4,4'-diphenyl-4''-([1,2'-binathyl]-6-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4,4'-diphenyl-4''-([2,2'-binathyl]-7-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4,4'-diphenyl-4''-([2,2'-binathyl]-6 ... 4,4'-diphenyl-4''-([1,2'-binathyl]-5-yl)triphenylamine (abbreviated as: BBAβNαNB), 4,4'-diphenyl-4''-([1,2'-binathyl]-5-yl)triphenylamine (abbreviated as: BBAβNαNB-02), 4-(4-biphenyl)-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviated as: TPBiAβNB), 4-(3-biphenyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviated as: mTPBiAβNBi), 4-(4-biphenyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviated as: TPBiAβNBi), 4-phenyl-4'-(1-naphthyl)triphenylamine (abbreviated as: αNBA1BP), 4,4'-Bis(1-naphthyl)triphenylamine (abbreviation: αNBB1BP), 4,4'-diphenyl-4''-[4'-(carbazole-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazole-9-yl)phenyl]tri(biphenyl-4-yl)amine (abbreviation: YGTBi1BP-02), 4-[4'-(carbazole-9-yl)biphenyl-4-yl]-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: YGTBiβNB), N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9'-spirodi[9H-fluorene]-2-amine (abbreviation: PCB) NBSF), N,N-bis(biphenyl-4-yl)-9,9'-spirodi[9H-fluorene]-2-amine (abbreviated as: BBASF), N,N-bis(biphenyl-4-yl)-9,9'-spirodi[9H-fluorene]-4-amine (abbreviated as: BBASF(4)), N-(biphenyl-2-yl)-N-(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirodi[9H-fluorene]-4-amine (abbreviated as: oFBiSF), N-(biphenyl-4-yl)-N-(9,9-dimethyl-9H-fluorene-2-yl)dibenzofuran-4-amine (abbreviated as: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthalene 4-phenyl-4'-(9-phenylfluorene-9-yl)triphenylamine (abbreviated as: BPAFLP), 4-phenyl-3'-(9-phenylfluorene-9-yl)triphenylamine (abbreviated as: mBPAFLP), 4-phenyl-4'-[4-(9-phenylfluorene-9-yl)phenyl]triphenylamine (abbreviated as: BPAFLBi), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as: PCBA1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as: PCBANB), 4,4'-bis(1-naphthyl)-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as: PCBANBB), N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirodi[9H-fluorene]-2-amine (abbreviated as: PCBASF), N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluorene-2-amine (abbreviated as: PCBiF), N,N-bis(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirodi-9H-fluorene-4-amine, N,N-bis(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirodi-9H-fluorene-3-amine, N,N-bis(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirodi-9H-fluorene-2-amine, N,N-bis(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirodi-9H-fluorene-1-amine, 9'-[3-(triphenylsilyl)phenyl]-9'H-9,3':6',9''-tricarbazole (abbreviated as PSiCzGI), etc.

[0234] In addition, as materials with hole transport capabilities, the following aromatic amine compounds can also be used: N,N'-bis(p-tolyl)-N,N'-diphenyl-p-phenylene diamine (abbreviated as DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB), 4,4'-bis(N-{4-[N'-(3-methylphenyl)-N'-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviated as DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviated as DPA3B), etc.

[0235] <The Fourth Organic Compound> The fourth organic compound is preferably a material that is acceptor of the third organic compound. As an acceptor substance, an organic compound having an electron-withdrawing group (halogen group, cyano group, etc.) is preferred, and an organic compound having at least one of a halogen group and a cyano group, wherein the number of at least one of the halogen group and the cyano group is four or more, is more preferred. Specific examples include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinone dimethylethane (F4-TCNQ), chloroquinone, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinone dimethylethane (F6-TCNNQ), and 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyrene-2-ylidene)malonitrile. In particular, compounds such as HAT-CN, in which electron-withdrawing groups are bonded to fused aromatic rings comprising multiple heteroatoms, are thermally stable and therefore preferred. Furthermore, [3] axylene derivatives with electron-withdrawing groups (especially halogen groups such as fluorine groups and cyano groups) are highly electron-accepting and therefore particularly preferred. Specifically, examples include: α,α',α''-1,2,3-cyclopropanetrimethylenetri[4-cyano-2,3,5,6-tetrafluorophenylacetonitrile], α,α',α''-1,2,3-cyclopropanetrimethylenetri[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)phenylacetonitrile], and α,α',α''-1,2,3-cyclopropanetrimethylenetri[2,3,4,5,6-pentafluorophenylacetonitrile]. In addition to the organic compounds mentioned above, transition metal oxides such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide can also be used as acceptor substances.

[0236] In the second layer, signals observed via electron spin resonance are preferred. For example, the spin density of a signal observed near a g value of 2.00 is preferably 1 × 10⁻⁶. 17 spins / cm 3 The above is preferred to be 1×10 18 spins / cm 3 The above is further preferred to be 1×10 19 spins / cm 3 Therefore, the second layer can be used as a charge generation layer. Furthermore, it allows for the fabrication of light-emitting devices with low driving voltage and high efficiency.

[0237] [Third Layer] A third layer can also be provided between the first and second intermediate layers to facilitate the smooth transfer of electrons between the two layers.

[0238] The third layer contains an electron-transporting material and is able to prevent the interaction between the first and second layers to facilitate electron transfer. The LUMO energy level of the electron-transporting material contained in the third layer 163 is preferably between the LUMO energy level of the acceptor material in the second layer 162 and the LUMO energy level of the organic compound contained in the layer in contact with the intermediate layer 160 in the light-emitting unit on the first electrode 101 side. Specifically, the LUMO energy level of the electron-transporting material used in the third layer 163 is -5.0 eV or higher, preferably -5.0 eV or higher and -3.0 eV or lower, more preferably -4.30 eV or higher and -3.00 eV or lower, and even more preferably -4.30 eV or higher and -3.30 eV or lower. At this level, electrons generated in the second layer can be easily injected into the first layer, thus suppressing the rise in the driving voltage of the light-emitting device, which is preferred. Furthermore, phthalocyanine materials or metal complexes having metal-oxygen bonds and aromatic ligands are preferably used as the electron-transporting material used in the third layer 163.

[0239] Specifically, perylene tetracarboxylic acid derivatives such as diquinoxolino[2,3-a:2',3'-c]phenazine (abbreviated as HATNA), 2,3,8,9,14,15-hexafluorodiquinoxolino[2,3-a:2',3'-c]phenazine (abbreviated as HATNA-F6), 3,4,9,10-perylene tetracarboxylic acid diimide (abbreviated as PTCDI), 3,4,9,10-perylene tetracarboxylic acid-bis-benzimidazole (abbreviated as PTCBI), (C60-Ih)[5,6]fullerene (abbreviated as C60), (C70-D5h)[5,6]fullerene (abbreviated as C70), and phthalocyanine (abbreviated as H2Pc) can be used. Alternatively, metal phthalocyanines containing copper, zinc, cobalt, chromium, nickel, etc., and their derivatives, such as copper phthalocyanine (CuPc), zinc phthalocyanine (ZnPc), cobalt phthalocyanine (CoPc), iron phthalocyanine (FePc), tin phthalocyanine (SnPc), tin phthalocyanine (SnOPc), titanium phthalocyanine (TiOPc), and vanadium phthalocyanine (VOPc), can be used. In particular, phthalocyanine metal complexes such as copper phthalocyanine or zinc phthalocyanine, or 2,3,8,9,14,15-hexafluorodiquinoxalino[2,3-a:2',3'-c]phenazine, are preferred.

[0240] In addition, the thickness of the third layer 163 is preferably 1 nm or more and 10 nm or less, more preferably 2 nm or more and 5 nm or less.

[0241] The structure shown in this embodiment can be appropriately combined with the structures shown in other embodiments.

[0242] Implementation Method 2 In this embodiment, other structures of the light-emitting device according to one aspect of the present invention are described.

[0243] Figure 8A The light-emitting device 130 is shown as an example of a light-emitting device according to one aspect of the present invention. The light-emitting device 130 is a light-emitting device comprising an organic compound layer 103 having a light-emitting layer 113 between a first electrode 101 having an anode and a second electrode 102 having a cathode.

[0244] Figure 8B Light-emitting device 130 is shown as another example of a light-emitting device according to one aspect of the present invention. Light-emitting device 130 is a series-connected light-emitting device. In light-emitting device 130, the organic compound layer 103 includes a first light-emitting unit 501 having a first light-emitting layer 113_1, a second light-emitting unit 502 having a second light-emitting layer 113_2, and an intermediate layer 160. The intermediate layer 160 includes a first layer 161, a second layer 162, and a third layer 163 located between the first layer 161 and the second layer 162.

[0245] Note that in this embodiment, a light-emitting device including an intermediate layer 160 and two light-emitting units is used as an example. However, a light-emitting device including an intermediate layer of n (n is an integer greater than 1) and light-emitting units of n+1 layers can also be used.

[0246] For example, Figure 8C The illustrated light-emitting device 130 is an example of a series-connected light-emitting device, where n is 2, and the organic compound layer 103 includes a first light-emitting unit 501, a first intermediate layer 160_1, a second light-emitting unit 502, a second intermediate layer 160_2, and a third light-emitting unit 503 including a third light-emitting layer 113_3. The color gamut of the light emitted by the light-emitting layers in each light-emitting unit can be the same or different. In addition, the light-emitting layer can have a single-layer structure or a multilayer structure. For example, by making the first and third light-emitting units emit light in the blue region and the multilayer light-emitting layer in the second light-emitting unit emit light in the red and green regions, white light can be obtained.

[0247] For example, Figure 8DThe illustrated light-emitting device 130 is an example of a series-connected light-emitting device, where n is 3, and the organic compound layer 103 includes a first light-emitting unit 501, a first intermediate layer 160_1, a second light-emitting unit 502, a second intermediate layer 160_2, a third light-emitting unit 503, a third intermediate layer 160_3, and a fourth light-emitting unit 504 including a fourth light-emitting layer 113_4. The color gamut of the light emitted by the light-emitting layers in each light-emitting unit can be the same or different. In addition, the light-emitting layer can have a single-layer structure or a stacked structure. For example, the four light-emitting units can adopt the following structures: a structure in which any three are blue (B) and the remaining one is green (G); a structure in which any two are blue (B) and the remaining two are yellow (Y); and a structure in which any one is red (R), the other is green (G), and the remaining two are blue (B), etc.

[0248] The light-emitting device 130 may also be a light-emitting device manufactured by lithography. When using a light-emitting device manufactured by lithography, at least the light-emitting layer 113 or the second light-emitting layer 113_2 and the organic compound layer closer to the first electrode 101 than the aforementioned layers are processed simultaneously, so that the ends of these layers are substantially aligned in the vertical direction.

[0249] In addition, the organic compound layer 103 may also include other functional layers besides the light-emitting layer. Figure 8A The structure is shown below: In addition to the light-emitting layer 113, the organic compound layer 103 also includes a hole injection layer 111, a hole transport layer 112, an electron transport layer 114, and an electron injection layer 115. Furthermore, the first light-emitting unit 501 and the second light-emitting unit 502 may also include other functional layers besides the light-emitting layer. Figure 8B The following structure is shown: The first light-emitting unit 501, in addition to the first light-emitting layer 113_1, also has a hole injection layer 111, a first hole transport layer 112_1, and a first electron transport layer 114_1. The second light-emitting unit 502, in addition to the second light-emitting layer 113_2, also has a second hole transport layer 112_2, a second electron transport layer 114_2, and an electron injection layer 115. Note that the structure of the organic compound layer 103 in this invention is not limited to this; it may omit any of the above layers or include other layers. Typical examples of other layers include carrier blocking layers (hole blocking layers, electron blocking layers), exciton blocking layers, etc.

[0250] Next, the structure other than the intermediate layer 160 of the light-emitting device 130 will be described.

[0251] <<Structure of the First Electrode>> The first electrode 101 is an electrode including an anode. The first electrode 101 may also have a multilayer structure, in which case the layer in contact with the organic compound layer 103 is used as the anode. The anode is preferably formed using a metal, alloy, conductive compound, or mixture thereof with a high work function (specifically 4.0 eV or higher). Specifically, examples include indium tin oxide (ITO), indium tin oxide containing silicon or silicon oxide, indium zinc oxide, and indium tin oxide (IWZO) containing tungsten oxide and zinc oxide. While these conductive metal oxide films are typically deposited by sputtering, they can also be formed using sol-gel methods. As an example of a formation method, an indium zinc oxide formation method using a target with 1 wt% to 20 wt% zinc oxide added to indium oxide can be described by sputtering. Alternatively, indium oxide (IWZO) containing tungsten oxide and zinc oxide can be formed by sputtering using a target containing 0.5 wt% to 5 wt% tungsten oxide and 0.1 wt% to 1 wt% zinc oxide. Other materials that can be used as the anode include, for example, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), or nitrides of metallic materials (e.g., titanium nitride). Graphene can also be used as the anode material. Furthermore, by using the second layer 162 of the aforementioned intermediate layer 160 as the layer in contact with the anode (typically a hole injection layer), the work function can be disregarded when selecting the electrode material.

[0252] <<Structure of the Hole Injection Layer>> The hole injection layer 111 is in contact with the anode and has the function of easily injecting holes into the organic compound layer 103 (first light-emitting unit 501). The hole injection layer 111 can be formed using phthalocyanine compounds such as H2Pc and CuPc; aromatic amine compounds such as DPAB and DNTPD; or polymers such as poly(3,4-ethylenedioxythiophene) / (polystyrene sulfonic acid) (abbreviated as PEDOT / PSS).

[0253] Alternatively, the hole injection layer 111 can also be formed using a material with electron acceptor properties. As an acceptor material, the aforementioned materials used as acceptor materials for the second layer 162 in the intermediate layer 160 can also be used.

[0254] Alternatively, the hole injection layer 111 can also be formed using the hole transport material used in the second layer 162 of the intermediate layer 160 described above.

[0255] Note that in the hole injection layer 111, the hole-transporting organic compound used in the composite material is more preferably a material with a low HOMO energy level, having a HOMO energy level of -5.7 eV or higher and -5.4 eV or lower. When the hole-transporting organic compound used in the composite material has a low HOMO energy level, holes are easily injected into the hole transport layer, and a long-lifetime light-emitting device can be easily obtained. Furthermore, when the hole-transporting organic compound used in the composite material is a material with a low HOMO energy level, hole induction is appropriately suppressed, thus enabling a light-emitting device with an even longer lifetime.

[0256] By forming a hole injection layer 111, hole injection capability can be improved, thereby obtaining a light-emitting device with low driving voltage.

[0257] Furthermore, in substances with receptors, organic compounds with receptors can be easily deposited using vapor deposition, making them easy-to-use materials.

[0258] In addition, since the second layer 162 in the intermediate layer 160 is used as a hole injection layer, the second light-emitting unit 502 does not have a hole injection layer, but the second light-emitting unit 502 may also have a hole injection layer.

[0259] <<Structure of the Hole Transport Layer>> The hole transport layers (first hole transport layer 112_1, second hole transport layer 112_2) are formed by containing organic compounds with hole transport properties. The organic compounds with hole transport properties preferably have a concentration of 1 × 10⁻⁶. -6 cm 2 Hole mobility above / Vs.

[0260] Examples of organic compounds with hole-transporting capabilities include: 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diaminobiphenyl (TPD), N,N'-bis(9,9'-spirobis[9H-fluorene]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (BSPB), BPAFLP, mBPAFLP, PCBA1BP, PCBBi1BP, PCBANB, PCCNBB, 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluorene-2-amine (PCBAF), PCBASF, and other compounds with aromatic amine skeletons.1,3-Bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-bis(N-carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), 3,3'-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP), 9,9'-bis(biphenyl-4-yl)-3,3'-bi-9H-carbazole (abbreviation: BisBPCz), 9,9'-bis(biphenyl-3-yl)-3,3'-bi-9H-carbazole (abbreviation: BisBPCz), 9-(biphenyl-3-yl)-9'-(biphenyl-4-yl)-9H,9'H-3,3'-bicarbazole ( Abbreviations: mBPCCBP), 9-(2-naphthyl)-9'-phenyl-3,3'-bi-9H-carbazole (abbreviation: βNCCP), 9-(3-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: βNCCmBP), 9-(4-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: βNCCBP), 9,9'-di-2-naphthyl-3,3'-9H,9'H-bicarbazole (abbreviation: BisβNCz), 9-(2-naphthyl)-9'-[1,1':4',1”-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9 -(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-5'-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':4',1"-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-(triphenyl-2-yl)-3,3'-9H,9'H Compounds with a carbazole skeleton, such as 'H-bicarbazole, 9-phenyl-9'-(triphenyl-2-yl)-3,3'-9H,9'H-bicarbazole (abbreviated as PCCzTp), 9,9'-bis(triphenyl-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(4-biphenyl)-9'-(triphenyl-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(triphenyl-2-yl)-9'-[1,1':3',1”-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, and 9-[3-(triphenylsilyl)phenyl]-3,9'-bi-9H-carbazole (abbreviated as PSiCzCz);Compounds with a thiophene skeleton, such as 4,4',4''-(benzyl-1,3,5-triyl)tris(dibenzothiophene) (abbreviated as DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]dibenzothiophene (abbreviated as DBTFLP-III), and 4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviated as DBTFLP-IV); and compounds with a furan skeleton, such as 4,4',4''-(benzyl-1,3,5-triyl)tris(dibenzofuran) (abbreviated as DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluorene-9-yl)phenyl]phenyl}dibenzofuran (abbreviated as mmDBFFLBi-II). Compounds with aromatic amine backbones and compounds with carbazole backbones are preferred due to their good reliability and high hole transport capacity, which helps to reduce the driving voltage. Furthermore, materials with hole transport capacity, such as those used as composite materials for the hole injection layer 111, can be appropriately used as materials constituting the hole transport layer. Moreover, organic compounds with amine and fluorene backbones are more preferred. Organic compounds with amine and fluorene backbones have high reliability and high hole transport capacity, thus reducing the power consumption of the light-emitting device, and are therefore preferred.

[0261] <<Structure of the Emitting Layer>> The light-emitting layers (light-emitting layer 113, first light-emitting layer 113_1, second light-emitting layer 113_2) preferably contain a light-emitting substance and a host material. Note that the light-emitting layers may also contain other materials. In addition, they may be two layers with different compositions.

[0262] The luminescent material can be a fluorescent luminescent material, a phosphorescent luminescent material, a material exhibiting thermally activated delayed fluorescence (TADF), or other luminescent materials.

[0263] In the luminescent layer, materials that can be used as fluorescent luminescent substances include, for example, the following substances. Note that other fluorescent luminescent substances can also be used.

[0264] Examples include 5,6-bis[4-(10-phenyl-9-anthrayl)phenyl]-2,2'-bipyridine (abbreviated as: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthrayl)biphenyl-4-yl]-2,2'-bipyridine (abbreviated as: PAPP2BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluorene-9-yl)phenyl]pyrene-1,6-diamine (abbreviated as: 1,6FLPAPrn), N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluorene-9-yl)phenyl]pyrene-1,6-diamine (abbreviated as: 1,6mMemFLPAPrn), N,N'-bis[4-( [9H-carbazole-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazole-9-yl)-4'-(10-phenyl-9-anthrayl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazole-9-yl)-4'-(9,10-diphenyl-2-anthrayl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthrayl)phenyl]-9H-carbazole-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra-tert-butylperylene (abbreviation: TBP), 4-(10-phenyl-9-anthrayl)-4'-(9-phenyl-9H-carbazole) -3-yl)triphenylamine (abbreviated as PCPAPA), N,N''-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene)bis(N,N',N'-triphenyl-1,4-phenylenediamine) (abbreviated as DPABPA), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthrayl)phenyl]-9H-carbazole-3-amine (abbreviated as 2PCAPPA), N-[4-(9,10-diphenyl-2-anthrayl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviated as 2DPAPPA), N,N,N',N',N'',N'',N''',N'''-octaphenyldibenzo[g,p]- 2,7,10,15-Tetraamine (abbreviated as: DBC1), Coumarin 30, N-(9,10-diphenyl-2-anthrayl)-N,9-diphenyl-9H-carbazole-3-amine (abbreviated as: 2PCAPA), N-[9,10-bis(biphenyl-2-yl)-2-anthrayl]-N,9-diphenyl-9H-carbazole-3-amine (abbreviated as: 2PCABPhA), N-(9,10-diphenyl-2-anthrayl)-N,N',N'-triphenyl-1,4-phenylene diamine (abbreviated as: 2DPAPA), 9,10-bis(2-biphenyl)-2-(N,N',N'-triphenyl-1,4-phenylene diamine-N-yl)anthracene (abbreviated as: 2DPABPhA), 9,10-Bis(biphenyl-2-yl)-N-[4-(9H-carbazol-9-yl)phenyl]-N-phenylanthracene-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenylanthracene-9-amine (abbreviation: DPhAPhA), coumarin 545T, N,N'-diphenylquinacridone (abbreviation: DPQd), rubrene, 5,12-bis(1,1'-biphenyl-4-yl)-6,11-diphenyltetraphenyl (abbreviation: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]vinyl}-6-methyl-4H-pyran-4-yl)malonitrile (abbreviation: DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro] -1H,5H-benzo[ij]quinazine-9-yl)vinyl]-4H-pyran-4-ylidene}malonium (abbreviation: DCM2), N,N,N',N'-tetra(4-methylphenyl)tetraphenyl-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetra(4-methylphenyl)acenaphthene[1,2-a]fluoranthene-3,10-diamine (abbreviation: p-mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinazine-9-yl)vinyl]-4H-pyran-4-ylidene}malonium (abbreviation: DC) JTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinazin-9-yl)vinyl]-4H-pyran-4-ylidene}malonium (abbreviation: DCJTB), 2-(2,6-bis{2-[4-(dimethylamino)phenyl]vinyl}-4H-pyran-4-ylidene)malonium (abbreviation: BisDCM), 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinazin-9-yl)vinyl]-4H-pyran-4-ylidene}malonium (abbreviation: BisDC) JTM), N,N'-diphenyl-N,N'-(1,6-pyrene-diyl)bis[(6-phenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), N,N'-diphenyl-N,N'-bis(9-phenyl-9H-carbazole-2-yl)naphtho[2,3-b;6,7-b']bisbenzofuran-3,10-diamine (abbreviation: 3,10PCA2Nbf(IV)-02), 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10FrA2Nbf(IV)-02), etc. In particular, 1,6FLPAPrn, 1,6mMemFLPAPrn, 1,Fused aromatic diamine compounds, such as pyrene diamine compounds like 6BnfAPrn-03, exhibit good hole trapping properties and high luminescence efficiency or good reliability, making them preferred choices.

[0265] In addition, 5,9-diphenyl-5H,9H-[1,4]benzozaborane[2,3,4-kl]phenazaborane (abbreviated as DABNA-1), 9-(biphenyl-3-yl)-N,N,5,11-tetraphenyl-5H,9H-[1,4]benzozaborane[2,3,4-kl]phenazaborane-3-amine (abbreviated as DABNA-2), and 2,12-bis(tert-butyl)-5,9-bis(4-tert-butylphenyl)-N,N-diphenyl-5H,9H-[1,4]benzozaborane[2,3,4-kl]phenazaborane can be used appropriately. Azabor-7-amine (abbreviation: DPhA-tBu4DABNA), 2,12-di(tert-butyl)-N,N,5,9-tetra(4-tert-butylphenyl)-5H,9H-[1,4]benzozaborane[2,3,4-kl]phenazabor-7-amine (abbreviation: tBuDPhA-tBu4DABNA), 2,12-di(tert-butyl)-5,9-di(4-tert-butylphenyl)-7-methyl-5H,9H-[1,4]benzozaborane[2,3,4-kl]phenazaborane (abbreviation: Me-tBu4DABNA), N 7 N 7 N 13 N 13 Nitrogen- and boron-containing fused heteroaromatic compounds, especially those with a diaza-boron-naphtho-anthracene skeleton, can produce blue luminescence with good color purity due to their narrow emission spectra.

[0266] In addition, compounds with an indole skeleton, such as 9,10,11-tris[3,6-bis(1,1-dimethylethyl)-9H-carbazole-9-yl]-2,5,15,18-tetra(1,1-dimethylethyl)indolo[3,2,1-de]indolo[3',2',1':8,1][1,4]benzozaborane[2,3,4-kl]phenazaborane (abbreviated as: BBCz-G) and 9,11-bis[3,6-bis(1,1-dimethylethyl)-9H-carbazole-9-yl]-2,5,15,18-tetra(1,1-dimethylethyl)indolo[3,2,1-de]indolo[3',2',1':8,1][1,4]benzozaborane[2,3,4-kl]phenazaborane (abbreviated as: BBCz-Y), can be appropriately used.

[0267] When phosphorescent materials are used as luminescent materials in the luminescent layer, the following substances can be cited as examples of usable materials.

[0268] Examples include organometallic iridium complexes with a 4H-triazole skeleton, such as tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN2]phenyl-κC}iridium(III) (abbreviated as [Ir(mpptz-dmp)3]), tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazole)iridium(III) (abbreviated as [Ir(Mptz)3]), and tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazole]iridium(III) (abbreviated as [Ir(iPrptz-3b)3]); and tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazole]iridium(III) (abbreviated as [... Organometallic iridium complexes with a 1H-triazole skeleton, such as [Ir(Prptz1-mp)3], tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazole)iridium(III) (abbreviated as [Ir(Prptz1-Me)3]); fac-tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazolium]iridium(III) (abbreviated as [Ir(iPrpim)3]), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviated as [Ir(dmpimpt-Me)3]), tris(2-{1-[2,6-bis(1-methylethyl)phenyl]-1H-imidazolium-2-yl-κN 3Organometallic iridium complexes with an imidazole skeleton, such as}-4-cyanophenyl-κC)iridium(III) (abbreviated as CNImIr); organometallic complexes with a benzimidazole skeleton, such as tris[(6-tert-butyl-3-phenyl-2H-imidazo[4,5-b]pyrazin-1-yl-κC2)phenyl-κC]iridium(III) (abbreviated as [Ir(cb)3]); bis[2-(4',6'-difluorophenyl)pyridinium-N,C 2’ Iridium(III) tetra(1-pyrazolyl)borate (abbreviated as: FIr6), bis[2-(4',6'-difluorophenyl)pyridinium-N,C 2’ Iridium(III) picolinate (FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinium-N,C 2’} Iridium(III)pyridinecarboxylate (abbreviated as: [Ir(CF3ppy)2(pic)]), bis[2-(4',6'-difluorophenyl)pyridin-N,C 2’ Organometallic iridium complexes with phenylpyridine derivatives having electron-withdrawing groups, such as iridium(III) acetylacetone (FIracac), and platinum complexes such as (2-{3-[3-(3,5-di-tert-butylphenyl)benzimidazol-1-yl-2-ylidene-κC2]phenoxy-κC2}-9-(4-tert-butyl-2-pyridyl-κN)carbazole-2,1-diyl-κC1)platinum(II) (PtON-TBBI), are examples of compounds that emit blue phosphorescence and have emission peaks in the wavelength region of 450 nm to 520 nm. Additionally, compounds containing deuterium as a part of their hydrogen content can also be used.

[0269] In addition, examples include: tris(4-methyl-6-phenylpyrimidine)iridium(III) (abbreviated as [Ir(mppm)3]), tris(4-tert-butyl-6-phenylpyrimidine)iridium(III) (abbreviated as [Ir(tBuppm)3]), (acetylacetonate)bis(6-methyl-4-phenylpyrimidine)iridium(III) (abbreviated as [Ir(mppm)2(acac)]), (acetylacetonate)bis(6-tert-butyl-4-phenylpyrimidine)iridium(III) (abbreviated as [Ir(tBuppm)2(acac)]), (acetylacetonate)bis[6-(2-norborneol)-4-phenylpyrimidine]iridium(III) (abbreviated as [Ir(nbppm)2(acac)]), (acetylacetonate)bis[5-methyl Organometallic iridium complexes with a pyrimidine skeleton, such as 6-(2-methylphenyl)-4-phenylpyrimidinium-iridium(III) (abbreviated as [Ir(mpmppm)2(acac)]) and (acetylacetonium-ionium)bis(4,6-diphenylpyrimidinium-ionium(III)) (abbreviated as [Ir(dppm)2(acac)]); organometallic iridium complexes with a pyrazine skeleton, such as (acetylacetonium-ionium)bis(3,5-dimethyl-2-phenylpyrazine-ionium(III)) (abbreviated as [Ir(mppr-Me)2(acac)]) and (acetylacetonium-ionium)bis(5-isopropyl-3-methyl-2-phenylpyrazine-ionium(III)) (abbreviated as [Ir(mppr-iPr)2(acac)]); tris(2-phenylpyridinium-N,C 2’ Iridium (III) (abbreviated as: [Ir(ppy)3]), bis(2-phenylpyridinium-N,C) 2’ Iridium (III) acetylacetone (abbreviated as: [Ir(ppy)2(acac)]), bis(benzo[h]quinoline)iridium (III) acetylacetone (abbreviated as: [Ir(bzq)2(acac)]), tri(benzo[h]quinoline)iridium (III) (abbreviated as: [Ir(bzq)3]), tri(2-phenylquinoline-N,C 2’ Iridium (III) (abbreviated as: [Ir(pq)3]), bis(2-phenylquinoline-N,C) 2’Iridium (III) acetylacetone (abbreviation: [Ir(pq)2(acac)]), [2-d3-methyl-8-(2-pyridyl-κN)benzofurano[2,3-b]pyridin-κC]bis[2-(5-d3-methyl-2-pyridyl-κN2)phenyl-κC]iridium (III) (abbreviation: Ir(5mppy-d3)2(mbfpypy-d3)), {2-(methyl-d3)-8-[4-(1-methylethyl-1-d)-2-pyridyl-κN]benzofurano[2,3-b]pyridin-7-yl-κC}bis{5-(methyl-d3)-2-[5-(methyl-d3)-2-pyridyl-κN]phenyl-κC}iridium (III) (abbreviated as: Ir(5mtpy-d6)2(mbfpypy-iPr-d4)), [2-(methyl-d3)-8-(2-pyridyl-κN)benzofurano[2,3-b]pyridin-κC]bis[2-(2-pyridyl-κN)phenyl-κC]iridium(III) (abbreviated as: Ir(ppy)2(mbfpypy-d3)), [2-(4-methyl-5-phenyl-2-pyridyl-κN)phenyl-κC]bis[2-(2-pyridyl-κN)phenyl-κC]iridium(III) (abbreviated as: Ir(ppy)2(mdppy)), [2-(4-d3-methyl-5-phenyl-2-pyridyl-κN2)phenyl [-κC]bis[2-(5-d3-methyl-2-pyridyl-κN2)phenyl-κC]iridium(III) (abbreviated as: [Ir(5mppy-d3)2(mdppy-d3)]), [2-methyl-8-(2-pyridyl-κN)benzofurano[2,3-b]pyridyl-κC]bis[2-(2-pyridyl-κN)phenyl-κC]iridium(III) (abbreviated as: [Ir(ppy)2(mbfpypy)]), tri{2-[5-(methyl-d3)-4-phenyl-2-pyridyl-κN]phenyl-κC}iridium(III) (abbreviated as: Ir(5m4dppy-d3)3) and other organometallic iridium complexes with a pyridine skeleton; tri(ethyl Rare earth metal complexes such as acetylacetone (monophenyline) terbium (III) (abbreviated as [Tb(acac)3(Phen)]), (2-{1-(5-tert-butylbiphenyl-2-yl)-4-[3-tert-butyl-5-(4-phenyl-2-pyridyl-κN)phenyl-κC6]-2-benzimidazolyl-κN3}-4,6-di-tert-butylphenol-κO) platinum (II) (abbreviated as Pt(tBudppymmtBubiz-tBubp)), [2-(4-(3,5-di-tert-butylphenyl)-6-{3-[4-(5'-tert-butyl[1,1':3',1''-tert-phenyl]-2'-yl)-2-pyridyl-κN]phenyl-κC 2Organometallic platinum complexes such as β-2-pyridyl-κN)phenol-κO]platinum(II) (abbreviated as Pt(4tButpppypyp-mmtBup)) are used. These substances are primarily compounds exhibiting green phosphorescence and possessing emission peaks in the 500 nm to 600 nm wavelength region. Furthermore, organometallic iridium complexes with a pyrimidine backbone are particularly preferred due to their exceptionally superior reliability or luminescent efficiency. Alternatively, compounds containing a portion of deuterium as hydrogen can also be used.

[0270] In addition, examples include organometallic iridium complexes with a pyrimidine skeleton, such as (diisobutyrylmethane)bis[4,6-bis(3-methylphenyl)pyrimidinium]iridium(III) (abbreviated as: [Ir(5mdppm)2(dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinium](dineopentylmethane)iridium(III) (abbreviated as: [Ir(5mdppm)2(dpm)]), and bis[4,6-bis(naphthyl-1-yl)pyrimidinium](dineopentylmethane)iridium(III) (abbreviated as: [Ir(d1npm)2(dpm)]). Organometallic iridium complexes with a pyrazine skeleton, such as bis(2,3,5-triphenylpyrazine)iridium(III) (abbreviated as [Ir(tppr)2(acac)]), bis(2,3,5-triphenylpyrazine)(dinepentylmethane)iridium(III) (abbreviated as [Ir(tppr)2(dpm)]), and (acetylacetonate)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviated as [Ir(Fdpq)2(acac)]); tris(1-phenylisoquinoline-N,C 2’ Iridium (III) (abbreviated as: [Ir(piq)3]), bis(1-phenylisoquinoline-N,C) 2’Organometallic iridium complexes with a pyridine skeleton include iridium(III) acetylacetone (abbreviated as [Ir(piq)2(acac)]), (3,7-diethyl-4,6-nonanedione-κO4,κO6)bis[2,4-dimethyl-6-[7-(1-methylethyl)-1-isoquinoline-κN]phenyl-κC]iridium(III), (3,7-diethyl-4,6-nonanedione-κO4,κO6)bis[2,4-dimethyl-6-[5-(1-methylethyl)-2-quinolinyl-κN]phenyl-κC]iridium(III). Platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) (abbreviated as PtOEP); and rare earth metal complexes such as tris(1,3-diphenyl-1,3-propanedionato) (monopraninol) europium(III) (abbreviated as [Eu(DBM)3(Phen)]) and tris[1-(2-thiophenecarboxyl)-3,3,3-trifluoroacetone] (monopraninol) europium(III) (abbreviated as [Eu(TTA)3(Phen)]). These substances are red phosphorescent compounds with emission peaks in the 600 nm to 700 nm wavelength region. Furthermore, organometallic iridium complexes with a pyrazine skeleton can obtain red emission with good chromaticity. Additionally, compounds containing a portion of deuterium as hydrogen can also be used.

[0271] In addition to the phosphorescent compounds mentioned above, other known phosphorescent compounds may also be used.

[0272] Fullerenes and their derivatives, acridines and their derivatives, and eosin derivatives can be used as TADF materials. In addition, metal porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd) can also be used. Examples of metalloporphyrins include, for instance, protoporphyrin-tin fluoride complexes represented by the following structural formulas: protoporphyrin-tin fluoride complex (SnF2(Proto IX)), mesotoporphyrin-tin fluoride complex (SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (SnF2(Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (SnF2(Copro III-4Me)), octaethylporphyrin-tin fluoride complex (SnF2(OEP)), protoporphyrin-tin fluoride complex (SnF2(Etio I)), and octaethylporphyrin-platinum chloride complex (PtCl2OEP).

[0273] [Chemical Formula 20] In addition, the following structural formulas can also be used: 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazole-11-yl)-1,3,5-triazine (abbreviated as: PIC-TRZ), 9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviated as: PCCzTzn), 2-{4-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviated as: PCCzPTzn), 2-[4-(10H-phenoxazine-10-yl)phenyl]-4,6-diphenyl-1,3 Heterocyclic compounds including 5-triazine (abbreviated: PXZ-TRZ), 3-[4-(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviated: PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-oxazanthracene-9-one (abbreviated: ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridin)phenyl]sulfone (abbreviated: DMAC-DPS), 10-phenyl-10H,10'H-spiro[acridin-9,9'-anthracene]-10'-one (abbreviated: ACRSA), etc., which include one or both of the π-electron-rich and π-electron-deficient heterocyclic rings. This heterocyclic compound is preferred because it includes both π-electron-rich and π-electron-deficient heteroaromatic rings, thus exhibiting high electron and hole transport properties. Among the skeletons comprising π-electron-deficient heteroaromatic rings, pyridine, diazine (pyrimidine, pyrazine, pyridazine), and triazine skeletons are stable and reliable, and are therefore preferred. In particular, benzofuran-pyrimidine, benzothiophene-pyrimidine, benzofuran-pyrazine, and benzothiophene-pyrazine skeletons exhibit high acceptor activity and good reliability, and are therefore preferred. Furthermore, among skeletons containing π-electron-rich heteroaromatic rings, acridine, phenoxazine, phenothiazine, furan, thiophene, and pyrrole skeletons are stable and reliable, and at least one of these skeletons is preferred. Moreover, dibenzofuran skeletons are preferred as furan skeletons, and dibenzothiophene skeletons are preferred as thiophene skeletons. As the pyrrole skeleton, indole, carbazole, indole-carbazole, bicarbazole, and 3-(9-phenyl-9H-carbazole-3-yl)-9H-carbazole skeletons are particularly preferred. Furthermore, in substances where π-electron-rich and π-electron-deficient heteroaromatic rings are directly bonded, the π-electron-rich heteroaromatic ring exhibits high electron-donating and electron-accepting properties, while the energy difference between the S1 and T1 energy levels is smaller, resulting in highly efficient thermally activated delayed fluorescence; therefore, it is particularly preferred. Note that aromatic rings bonded with electron-withdrawing groups such as cyano groups can also be used instead of π-electron-deficient heteroaromatic rings.Furthermore, as π-electron-rich skeletons, aromatic amine skeletons, phenazine skeletons, etc., can be used. Conversely, as π-electron-deficient skeletons, oxanthene skeletons, thioxanthene dioxide skeletons, oxadiazole skeletons, triazole skeletons, imidazole skeletons, anthraquinone skeletons, boron-containing skeletons such as phenylborane and boranthrene, aromatic rings with nitrile or cyano groups such as benzonitrile or cyanobenzene, heteroaromatic rings, carbonyl skeletons such as benzophenone, phosphine oxide skeletons, sulfone skeletons, etc., can be used. Thus, π-electron-deficient and π-electron-rich skeletons can be used to replace at least one of the π-electron-deficient and π-electron-rich heteroaromatic rings.

[0274] [Chemical Formula 21] Furthermore, TADF materials that are in thermal equilibrium between singlet and triplet excited states can also be used as TADF materials. Because of their short luminescence lifetime (excitation lifetime), these TADF materials can suppress efficiency degradation in the high-brightness region of light-emitting devices. Specifically, materials with the following molecular structures can be cited as examples.

[0275] [Chemical Formula 22] Note that TADF materials refer to materials with a small energy difference between the S1 and T1 levels and the ability to convert triple excitation energy into single excitation energy through antisystem crossing. Therefore, they can upconvert triple excitation energy into single excitation energy (antisystem crossing) with minimal thermal energy and efficiently generate singlet excited states. Furthermore, triple excitation energy can be converted into luminescence.

[0276] Exciplexes formed by two substances in an excited state have the function of converting triple excitation energy into single excitation energy due to the extremely small energy difference between the S1 and T1 energy levels.

[0277] Note that the phosphorescence spectrum observed at low temperatures (e.g., 77K to 10K) can be used as an indicator of the T1 energy level. For TADF materials, it is preferable that the energy difference between the S1 and T1 energy levels is 0.3 eV or less, more preferably 0.2 eV or less, when the wavelength energy of the extrapolated line obtained by tangenting at the short-wavelength side of the fluorescence spectrum is taken as the S1 energy level and the wavelength energy of the extrapolated line obtained by tangenting at the short-wavelength side of the phosphorescence spectrum is taken as the T1 energy level.

[0278] Furthermore, when using TADF material as the luminescent material, the S1 energy level of the host material is preferably higher than that of the TADF material. Additionally, the T1 energy level of the host material is preferably higher than that of the TADF material.

[0279] As the main material of the light-emitting layer, various carrier transport materials such as materials with electron transport properties and / or materials with hole transport properties, the aforementioned TADF materials, etc., can be used.

[0280] As a material with hole transport properties, the aforementioned materials with hole transport properties can be used in the same way.

[0281] As a material with electron transport properties, the aforementioned materials with electron transport properties can be used in the same way.

[0282] As a TADF material that can be used as the host material, the materials mentioned above as TADF materials can also be used. When a TADF material is used as the host material, the triple excitation energy generated by the TADF material is converted into a single excitation energy via antisystem crossing and further transferred to the luminescent material, thereby improving the luminous efficiency of the light-emitting device. In this case, the TADF material acts as an energy donor, and the luminescent material acts as an energy acceptor.

[0283] This is highly effective when the luminescent material is a fluorescent luminescent material. Furthermore, to obtain high luminescent efficiency, the S1 energy level of the TADF material is preferably higher than the S1 energy level of the fluorescent luminescent material. Additionally, the T1 energy level of the TADF material is preferably higher than the S1 energy level of the fluorescent luminescent material. Therefore, the T1 energy level of the TADF material is preferably higher than the T1 energy level of the fluorescent luminescent material.

[0284] Furthermore, it is preferable to use a TADF material that exhibits luminescence with a wavelength overlapping the absorption band on the lowest energy side of the fluorescent luminescent material. This allows for efficient transfer of excitation energy from the TADF material to the fluorescent luminescent material, resulting in highly efficient luminescence, and is therefore preferred.

[0285] To efficiently generate a singlet excitation energy from a triplet excitation energy via antisystem crossing, it is preferable to generate carrier recombination within the TADF material. Furthermore, it is preferable that the triplet excitation energy generated in the TADF material does not transfer to the triplet excitation energy of the fluorescent luminescent material. For this purpose, the fluorescent luminescent material preferably has a protecting group surrounding the luminescent body (the backbone that causes luminescence) of the fluorescent luminescent material. This protecting group is preferably a substituent without π bonds, preferably a saturated hydrocarbon, specifically alkyl groups with 3 or more but less than 10 carbon atoms, substituted or unsubstituted cycloalkyl groups with 3 or more but less than 10 carbon atoms, and trialkylsilyl groups with 3 or more but less than 10 carbon atoms; more preferably, it has multiple protecting groups. Substituents without π bonds have almost no function in transporting charge carriers, so they have little effect on charge carrier transport or carrier recombination, allowing the TADF material and the luminescent body of the fluorescent luminescent material to be kept apart. Here, the luminescent body refers to the atomic group (backbone) in the fluorescent luminescent material that causes luminescence. The luminescent material preferably has a π-bonded framework, preferably including an aromatic ring, and even more preferably including a fused aromatic ring or a fused heteroaromatic ring. Examples of such luminescent materials include phenanthrene, stilbene, acridinone, phenoxazine, phenothiazine, naphthalene, anthracene, fluorene, β-carbamate, triphenylene, tetraphenylene, pyrene, perylene, coumarin, quinacridone, and naphthobisbenzofuran frameworks. In particular, fluorescent luminescent materials having naphthalene, anthracene, fluorene, β-carbamate, triphenylene, tetraphenylene, pyrene, perylene, coumarin, quinacridone, and naphthobisbenzofuran frameworks exhibit high fluorescence quantum yields and are therefore preferred.

[0286] When using a fluorescent luminescent material as the luminescent material, a material with an anthracene framework is preferably used as the host material. By using a material with an anthracene framework as the host material of the fluorescent luminescent material, a luminescent layer with both high luminous efficiency and durability can be achieved. Among the anthracene framework materials used as host materials, those with a diphenylanthracene framework, especially those with a 9,10-diphenylanthracene framework, are chemically stable and therefore preferred. Furthermore, when the host material has a carbazole framework, hole injection / transport is improved, which is also preferred. However, when the host material has a benzo[a]carbazole framework with a benzene ring fused to the carbazole framework, the HOMO is about 0.1 eV higher than that of a host material with a carbazole framework, making hole injection easier, and therefore more preferred. In particular, when the host material has a dibenzo[a]carbazole framework, its HOMO is about 0.1 eV higher than that of a host material with a carbazole framework. In this case, not only is hole injection easier, but hole transport and heat resistance are also improved, making it preferred. Therefore, as the host material, a substance having both a 9,10-diphenylanthracene skeleton and a carbazole skeleton (or a benzo[a]carbazole skeleton or a dibenzo[a]carbazole skeleton) is further preferred. Note that from the viewpoint of hole injection / transportation described above, a benzo[a]fluorene skeleton or a dibenzo[a]fluorene skeleton can also be used instead of a carbazole skeleton. Examples of such substances include 9-phenyl-3-[4-(10-phenyl-9-anthrayl)phenyl]-9H-carbazole (abbreviated: PCzPA), 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviated: PCPN), 9-[4-(10-phenyl-9-anthrayl)phenyl]-9H-carbazole (abbreviated: CzPA), 7-[4-(10-phenyl-9-anthrayl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviated: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthrayl)phenyl]benzo[b]naphtho[1,2-d]furan (abbreviated: 2mBnfPPA), and 9-phenyl-10-[4'-(9-phenyl-9H-fluorene-9-yl] Biphenyl-4-yl]anthracene (abbreviated as FLPPA), 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviated as αN-βNPAnth), 9-(1-naphthyl)-10-(2-naphthyl)anthracene (abbreviated as α,β-ADN), 2-(10-phenylanthracene-9-yl)dibenzofuran, 2-(10-phenyl-9-anthrayl)benzo[b]naphtho[2,3-d]furan (abbreviated as Bnf(II)PhA), 9-(2-naphthyl)-10-[3-(2-naphthyl)phenyl]anthracene (abbreviated as βN-mβNPAnth), 1-{4-[10-(biphenyl-4-yl)-9-anthrayl]phenyl}-2-ethyl-1H-benzimidazole (abbreviated as EtBImPBPhA), etc. In particular, CzPA, cgDBCzPA, 2mBnfPPA, and PCzPA exhibit very good properties and are therefore preferred.

[0287] Furthermore, the host material can also be a mixture of multiple substances. When using a mixed host material, it is preferable to mix materials with electron transport properties and materials with hole transport properties. By mixing materials with electron transport properties and materials with hole transport properties, it is easier to adjust the transport properties of the light-emitting layer 113 and to more easily control the rebinding region. The weight ratio of the material with hole transport properties to the material with electron transport properties can be from 1:19 to 19:1.

[0288] Note that phosphorescent materials can be used as part of the above-described mixture. When used as a fluorescent material, the phosphorescent material can be used as an energy donor to supply excitation energy to the fluorescent material.

[0289] Furthermore, these mixed materials can also be used to form excimer complexes. By selecting a combination of excimer complexes that form light with wavelengths overlapping the absorption band on the lowest energy side of the luminescent material, energy transfer can be facilitated, resulting in efficient luminescence, which is therefore preferred. Furthermore, the driving voltage is also reduced by employing this structure, making it also preferred.

[0290] Note that at least one of the materials forming the excitocomplex can also be a phosphorescent material. This allows for the efficient conversion of triple excitation energy into single excitation energy via antisystem crossing.

[0291] Regarding the combination of materials for efficiently forming excitocomplexes, the HOMO energy level of the material with hole transport is preferably above the HOMO energy level of the material with electron transport. Furthermore, the LUMO energy level of the material with hole transport is preferably above the LUMO energy level of the material with electron transport. Note that the LUMO and HOMO energy levels of the material can be determined from the electrochemical properties (reduction potential and oxidation potential) of the material measured by cyclic voltammetry (CV).

[0292] Note that the formation of excitocomplexes can be confirmed, for example, by comparing the emission spectra of a hole-transporting material, the emission spectra of an electron-transporting material, and the emission spectra of a hybrid film formed by mixing these materials. When the emission spectrum of the hybrid film is observed to shift towards a longer wavelength (or to have a new peak on the longer wavelength side) compared to the emission spectra of each material, it indicates the formation of an excitocomplex. Alternatively, by comparing the transient photoluminescence (PL) of a hole-transporting material, the transient PL of an electron-transporting material, and the transient PL of a hybrid film formed by mixing these materials, when a difference in transient response is observed, such as the mixed film having a longer lifetime component or a higher ratio of delayed components compared to the transient PL lifetimes of each material, it indicates the formation of an excitocomplex. Furthermore, the aforementioned transient PL can be referred to as transient electroluminescence (EL). In other words, by comparing the transient EL of a hole-transporting material, the transient EL of an electron-transporting material, and the transient EL of a hybrid film of these materials, and observing the differences in transient responses, the formation of an excitocomplex can be confirmed.

[0293] <<Structure of the Electron Transport Layer>> The electron transport layer (electron transport layer 114, first electron transport layer 114_1, second electron transport layer 114_2) is a layer containing a material with electron transport properties. Preferably, the electron mobility of the material with electron transport properties is 1×10⁻⁶ when the square root of the electric field strength [V / cm] is 600. -7 cm 2 / Vs or more, preferably 1×10 -6 cm 2 Substances with a value of / Vs or higher. Furthermore, any substance other than those described above can be used, as long as its electron transport capability is higher than its hole transport capability. As the aforementioned organic compounds, organic compounds comprising π-electron-deficient heteroaromatic rings are preferred. For example, one or more of the following are preferred: organic compounds comprising a heteroaromatic ring with an azole skeleton, organic compounds comprising a heteroaromatic ring with a pyridine skeleton, organic compounds comprising a heteroaromatic ring with a diazine skeleton, and organic compounds comprising a heteroaromatic ring with a triazine skeleton.

[0294] As for the aforementioned electron-transporting organic compounds that can be used in the electron transport layer, similarly, organic compounds that can be used as the first layer of the intermediate layer 160 can be used. In particular, organic compounds comprising heteroaromatic rings with a diazine skeleton, organic compounds comprising heteroaromatic rings with a pyridine skeleton, or organic compounds comprising heteroaromatic rings with a triazine skeleton are preferred due to their good reliability. In particular, organic compounds comprising heteroaromatic rings with a diazine (pyrimidine or pyrazine) skeleton and organic compounds comprising heteroaromatic rings with a triazine skeleton have high electron transport properties, which helps to reduce the driving voltage.

[0295] Furthermore, the electron transport layer preferably has an electron mobility of 1×10⁻⁶ when the square root of the electric field strength [V / cm] is 600. -7 cm 2 / Vs or more and 5×10 -5 cm 2 / Vs or less. By reducing the electron transport property in the electron transport layer, the amount of electrons injected into the light-emitting layer can be controlled, thereby preventing the light-emitting layer from becoming an electron-overloaded state. When a hole injection layer is formed using a composite material, and the HOMO energy level of the hole-transporting material in this composite material is a low HOMO energy level of -5.7 eV or higher and -5.4 eV or lower, a long lifetime can be obtained by adopting the above structure, and therefore it is particularly preferred. Note that in this case, the HOMO energy level of the electron-transporting material is preferably -6.0 eV or higher.

[0296] For example, heteroaromatic compounds can be used as electron transport materials for electron transport layers. Note that heteroaromatic compounds refer to cyclic compounds containing at least two different elements in the ring. Note that the ring structure includes three-membered rings, four-membered rings, five-membered rings, six-membered rings, etc., with five-membered or six-membered rings being particularly preferred. The elements contained in the heteroaromatic compound, besides carbon, are preferably one or more of nitrogen, oxygen, and sulfur. Nitrogen-containing heteroaromatic compounds are particularly preferred (nitrogen-containing heteroaromatic compounds), and materials with high electron transport properties (electron transport materials) such as nitrogen-containing heteroaromatic compounds or π-electron-deficient heteroaromatic compounds containing such nitrogen-containing heteroaromatic compounds are preferred. The compound of Embodiment 1 can be used as an electron transport material because it possesses electron transport properties.

[0297] Note that the electron transport material can be a different material than the material used for the emitting layer. Not all excitons generated in the emitting layer through carrier recombination necessarily contribute to luminescence; sometimes they diffuse into layers in contact with or near the emitting layer. To avoid this phenomenon, the energy levels (lowest singlet or lowest triplet excitation level) of the material used for the material in contact with or near the emitting layer are preferably higher than those of the material used for the emitting layer. Therefore, when a different material is used for the electron transport material than for the emitting layer, a highly efficient device can be obtained.

[0298] Heteroaromatic compounds are organic compounds that include at least one heteroaromatic ring.

[0299] Note that heteroaromatic rings include any one of pyridine rings, diazine rings, triazine rings, azole rings, oxazole rings, and thiazole rings. Furthermore, heteroaromatic rings including pyrimidine rings, pyrazine rings, or pyridazine rings are included in heteroaromatic rings including diazine rings. Additionally, heteroaromatic rings including imidazole rings, triazole rings, and oxadiazole rings are included in heteroaromatic rings including azole rings.

[0300] Heteroaromatic rings include fused heteroaromatic rings with fused ring structures. Note that examples of fused heteroaromatic rings include quinoline rings, benzoquinoline rings, quinoxaline rings, dibenzoquinoxaline rings, quinazoline rings, benzoquinazoline rings, dibenzoquinazoline rings, phenanthrene rings, furan-diazine rings, and benzimidazole rings.

[0301] Note that, for example, among heteroaromatic compounds that contain one or more of nitrogen, oxygen, and sulfur in addition to carbon, examples of heteroaromatic compounds having a five-membered ring structure include heteroaromatic compounds with imidazole rings, heteroaromatic compounds with triazole rings, heteroaromatic compounds with oxazole rings, heteroaromatic compounds with oxadiazole rings, heteroaromatic compounds with thiazole rings, and heteroaromatic compounds with benzimidazole rings.

[0302] For example, among heteroaromatic compounds that contain one or more of nitrogen, oxygen, and sulfur in addition to carbon, examples of heteroaromatic compounds having a six-membered ring structure include heteroaromatic compounds with heteroaromatic rings such as pyridine rings, diazine rings (including pyrimidine rings, pyrazine rings, pyridazine rings, etc.), triazine rings, and azole rings. Note that examples include heteroaromatic compounds with bipyridine structures and heteroaromatic compounds with terpyridine structures, which are included among heteroaromatic compounds with pyridine rings.

[0303] Furthermore, examples of heteroaromatic compounds having a fused ring structure in which a portion of the aforementioned six-membered ring structure can be fused heteroaromatic compounds having quinoline rings, benzoquinoline rings, quinoxaline rings, dibenzoquinoxaline rings, phenanthrene rings, furanodiazine rings (including structures where the furan ring of the furanodiazine ring is fused with an aromatic ring), benzimidazole rings, and other fused heteroaromatic rings.

[0304] As specific examples of the heteroaromatic compounds having a five-membered ring structure and the heteroaromatic compounds having a six-membered ring structure, materials identical to the electron transport material shown in Embodiment 1 can be cited.

[0305] In addition to the aforementioned heteroaromatic compounds, the electron transport layer can also utilize the following metal complexes. Examples of such metal complexes include tris(8-hydroxyquinoline)aluminum(III) (Alq3), Almq3, 8-hydroxyquinoline-lithium (Liq), BeBq2, bis(2-methyl-8-hydroxyquinoline)(4-phenylphenol)aluminum(III) (BAlq), bis(8-hydroxyquinoline)zinc(II) (Znq), and other metal complexes with quinoline or benzoquinoline rings; bis[2-(2-benzoxazolyl)phenol]zinc(II) (ZnPBO), bis[2-(2-benzothiazolyl)phenol]zinc(II) (ZnBTZ), and other metal complexes with oxazole or thiazole rings.

[0306] In addition, as electron transport materials, polymers such as poly(2,5-pyridinediyl) (abbreviated as PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviated as PF-Py), and poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)] (abbreviated as PF-BPy) can also be used.

[0307] In addition, the electron transport layer is not limited to a single layer; it can also be a structure consisting of two or more layers made of the aforementioned materials.

[0308] The electron injection layer 115 can also be composed of alkali metals, alkaline earth metals, rare earth metals, or their compounds or complexes, such as lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), 8-hydroxyquinoline-lithium (Liq), and ytterbium (Yb). The electron injection layer 115 can be a layer or an electron compound containing alkali metals, alkaline earth metals, or their compounds within a layer composed of a substance with electron transport properties. Examples of electron compounds include, for instance, a mixture of calcium and aluminum oxides to which electrons are added at a high concentration.

[0309] Note that, as the electron injection layer 115, a layer may also be used that contains, at a concentration of 50 wt% or more, of the aforementioned alkali metal or alkaline earth metal fluorides in a microcrystalline state, comprising a substance with electron transport properties (preferably an organic compound having a bipyridine framework). Since this layer has a low refractive index, it can provide a light-emitting device with better external quantum efficiency.

[0310] Alternatively, layer 200 as described in embodiment 1 can also be used as electron injection layer 115.

[0311] <<Structure of the Second Electrode>> The second electrode 102 is an electrode that includes a cathode. The second electrode 102 may also have a stacked structure, in which case the layer in contact with the organic compound layer 103 serves as the cathode. As the material forming the cathode, metals, alloys, conductive compounds, and mixtures thereof with low work functions (specifically below 3.8 eV) can be used. Specific examples of such cathode materials include alkali metals such as lithium (Li) or cesium (Cs), elements belonging to Group 1 or Group 2 of the periodic table such as magnesium (Mg), calcium (Ca), or strontium (Sr), alloys containing them (MgAg, AlLi), rare earth metals such as europium (Eu), ytterbium (Yb), and alloys containing them. However, by providing an electron injection layer between the second electrode 102 and the electron transport layer, various conductive materials such as Al, Ag, ITO, and indium oxide-tin oxide containing silicon or silicon oxide can be used as the cathode regardless of the work function.

[0312] When the second electrode 102 is formed using a material that is transmissive to visible light, a light-emitting device that emits light from one side of the second electrode 102 can be formed.

[0313] These conductive materials can be deposited using dry methods such as vacuum evaporation and sputtering, as well as inkjet printing and spin coating. Alternatively, they can be formed using wet methods such as sol-gel processes or wet methods using pastes of metallic materials.

[0314] Furthermore, various methods, whether dry or wet, can be used to form the organic compound layer 103. For example, vacuum evaporation, gravure printing, offset printing, screen printing, inkjet printing, or spin coating can also be used.

[0315] In addition, the aforementioned electrodes or layers can also be formed using different deposition methods.

[0316] This embodiment can be appropriately combined with other embodiments or examples. Furthermore, where multiple structural examples are shown in one embodiment in this specification, these structural examples can be appropriately combined.

[0317] Implementation Method 3 like Figure 9A and Figure 9B As shown, a plurality of light-emitting devices 130 are formed on an insulating layer 175 to constitute a display device. In this embodiment, a display device according to one aspect of the present invention will be described in detail.

[0318] The display device 100 includes a pixel section 177 in which a plurality of pixels 178 are arranged in a matrix. The pixels 178 include sub-pixels 110R, 110G, and 110B.

[0319] In this specification, etc., the term "subpixel 110" is sometimes used to describe the common content among subpixels 110R, 110G, and 110B. Regarding other constituent elements distinguished by letters, symbols omitting the letters are sometimes used to indicate the common content among these constituent elements.

[0320] Subpixel 110R emits red light, subpixel 110G emits green light, and subpixel 110B emits blue light. Thus, an image can be displayed on pixel unit 177. Note that in this embodiment, only subpixels of three colors—red (R), green (G), and blue (B)—are used as an example for explanation; other colors of subpixels can also be combined. Furthermore, the number of subpixels is not limited to three; it can be four or more. Examples of four subpixels include: subpixels of four colors—R, G, B, and white (W); subpixels of four colors—R, G, B, and yellow (Y); and subpixels of four colors—R, G, B, and infrared (IR); etc.

[0321] In this specification, the row direction is sometimes referred to as the X direction and the column direction as the Y direction. The X direction and the Y direction intersect, for example, perpendicularly.

[0322] exist Figure 9A In the example shown, subpixels of different colors are arranged in the X direction, and subpixels of the same color are arranged in the Y direction. Note that subpixels of different colors can also be arranged in the Y direction, and subpixels of the same color can also be arranged in the X direction.

[0323] A connecting portion 140 may be provided on the outer side of the pixel portion 177, and a region 141 may also be provided thereon. The region 141 is provided between the pixel portion 177 and the connecting portion 140. An organic compound layer 103 is provided in the region 141. In addition, a conductive layer 151C is provided in the connecting portion 140.

[0324] exist Figure 9A In the example shown, region 141 and connecting portion 140 are located to the right of pixel portion 177, but there are no particular restrictions on the position of region 141 and connecting portion 140. Furthermore, region 141 and connecting portion 140 may be one or more.

[0325] Figure 9B It is along Figure 9A An example of a cross-sectional view of the dashed-dot line A1-A2 in the diagram. For example... Figure 9BAs shown, the display device 100 includes an insulating layer 171, a conductive layer 172 on the insulating layer 171, an insulating layer 173 on the insulating layer 171 and the conductive layer 172, an insulating layer 174 on the insulating layer 173, and an insulating layer 175 on the insulating layer 174. The insulating layer 171 is disposed on a substrate (not shown). The insulating layers 175, 174, and 173 are provided with openings leading to the conductive layer 172, and a plug 176 is disposed such that it is inserted into the openings.

[0326] In the pixel section 177, a light-emitting device 130 is disposed on the insulating layer 175 and the plug 176. Furthermore, a protective layer 135 is disposed to cover the light-emitting device 130. A substrate 120 is bonded to the protective layer 135 by a resin layer 122. Additionally, it is preferable to provide an inorganic insulating layer 125 and an insulating layer 127 on the inorganic insulating layer 125 between adjacent light-emitting devices 130.

[0327] Figure 9B Cross-sections of multiple inorganic insulating layers 125 and multiple insulating layers 127 are shown, but when viewed from above the display device 100, the inorganic insulating layers 125 and insulating layers 127 are preferably formed as continuous layers. In other words, the inorganic insulating layers 125 and insulating layers 127 are preferably insulating layers having openings on the first electrode.

[0328] Figure 9B Light-emitting devices 130R, 130G, and 130B are shown as light-emitting device 130. Light-emitting devices 130R, 130G, and 130B emit light of different colors from each other. For example, light-emitting device 130R may emit red light, light-emitting device 130G may emit green light, and light-emitting device 130B may emit blue light. Alternatively, light-emitting devices 130R, 130G, or 130B may also emit other visible or infrared light.

[0329] One aspect of the display device of the present invention may include a top-emitting structure (top-emitting structure) that emits light in a direction opposite to that of the substrate on which the light-emitting device is formed. Alternatively, another aspect of the display device of the present invention may include a bottom-emitting structure (bottom-emitting structure).

[0330] Examples of luminescent materials contained in the light-emitting device 130 include organic compounds or organometallic complexes that emit fluorescence (fluorescent materials), emit phosphorescence (phosphorescent materials), and exhibit thermally activated delayed fluorescence (TADF) materials. Alternatively, inorganic compounds such as quantum dots may also be used.

[0331] The light-emitting device 130R has the structure shown in Embodiment 1. The light-emitting device 130R includes a first electrode (pixel electrode) composed of conductive layers 151R and 152R, an organic compound layer 103R on the first electrode, a common layer 104 on the organic compound layer 103R, and a second electrode (common electrode) 102 on the common layer. The common layer 104 may or may not be provided, but its presence reduces damage to the organic compound layer 103R during processing, making it preferred. When the common layer 104 is provided, it is preferably an electron injection layer. Furthermore, without the common layer 104, the organic compound layer 103R corresponds to the organic compound layer 103 in Embodiments 1 and 2. When the common layer 104 is provided, the stacked structure of the organic compound layer 103R and the common layer 104 corresponds to the organic compound layer 103 in Embodiments 1 and 2.

[0332] The light-emitting device 130G has the structure shown in Embodiment 1. The light-emitting device 130G includes a first electrode (pixel electrode) composed of conductive layers 151G and 152G, an organic compound layer 103G on the first electrode, a common layer 104 on the organic compound layer 103G, and a second electrode (common electrode) 102 on the common layer. The common layer 104 may or may not be provided, but its presence reduces damage to the organic compound layer 103G during processing, making it preferred. Furthermore, without the common layer 104, the organic compound layer 103G is equivalent to the organic compound layer 103 in Embodiments 1 and 2. With the common layer 104, the stacked structure of the organic compound layer 103G and the common layer 104 is equivalent to the organic compound layer 103 in Embodiments 1 and 2.

[0333] The light-emitting device 130B has the structure shown in Embodiment 1. The light-emitting device 130B includes a first electrode (pixel electrode) composed of conductive layers 151B and 152B, an organic compound layer 103B on the first electrode, a common layer 104 on the organic compound layer 103B, and a second electrode (common electrode) 102 on the common layer. The common layer 104 may or may not be provided, but its presence reduces damage to the organic compound layer 103B during processing, making it preferred. Furthermore, without the common layer 104, the organic compound layer 103B is equivalent to the organic compound layer 103 in Embodiments 1 and 2. With the common layer 104, the stacked structure of the organic compound layer 103B and the common layer 104 is equivalent to the organic compound layer 103 in Embodiments 1 and 2.

[0334] In a light-emitting device, one of the pixel electrode and the common electrode is used as the anode, and the other is used as the cathode. Unless otherwise specified, the following description assumes that the pixel electrode is used as the anode and the common electrode is used as the cathode.

[0335] Organic compound layers 103R, 103G, and 103B are arranged independently in an island-like configuration according to each device or each luminescent color. By arranging the organic compound layers 103 in an island-like configuration according to each luminescent device 130, leakage current between adjacent luminescent devices 130 can be suppressed in high-definition display devices. This prevents crosstalk and enables display devices with extremely high contrast. In particular, it enables display devices with high current efficiency at low brightness.

[0336] An island-shaped organic compound layer 103 is formed by depositing an EL film and processing the EL film using photolithography.

[0337] Furthermore, in one embodiment of the display device of the present invention, the first electrode (pixel electrode) of the light-emitting device preferably has a stacked structure. For example, in Figure 9B In the example shown, the first electrode of the light-emitting device 130 has a stacked structure of conductive layers 151 (151R, 151G, 151B) and conductive layers 152 (152R, 152G, 152B). For example, when the display device 100 has a top-emitting structure and the pixel electrode of the light-emitting device 130 is used as the anode, the conductive layer 151 is preferably a layer with high visible light reflectivity, and the conductive layer 152 is preferably a layer with, for example, visible light transmittance and a large work function. When the display device 100 has a top-emitting structure, the higher the visible light reflectivity of the pixel electrode, the higher the extraction efficiency of the light emitted by the organic compound layer 103. In addition, when the pixel electrode is used as the anode, the larger the work function of the pixel electrode, the easier it is to inject holes into the organic compound layer 103. Thus, by having a stacked structure of a conductive layer 151 with high visible light reflectivity and a conductive layer 152 with a large work function in the pixel electrode of the light-emitting device 130, the light-emitting device 130 can be a light-emitting device with high light extraction efficiency and low driving voltage. Note that in this specification, when describing the common elements among conductive layers 151R, 151G, and 151B, they are sometimes referred to as conductive layer 151.

[0338] When the conductive layer 151 is a layer with high visible light reflectivity, the visible light reflectivity of the conductive layer 151 is preferably, for example, 40% or more and 100% or less, or 70% or more and 100% or less. Furthermore, when the conductive layer 152 is an electrode with visible light transmittance, the visible light transmittance is preferably, for example, 40% or more.

[0339] In cases where the pixel electrode has a multi-layered stacked structure, the pixel electrode may sometimes deteriorate due to reactions between these layers. For example, when removing the film formed after the pixel electrode is formed by wet etching, galvanic corrosion may occur due to the contact of the chemical solution with the pixel electrode.

[0340] Therefore, in the display device 100 of this embodiment, insulating layers 156 (156R, 156G, 156B) are formed on the sides of conductive layers 151 and 152. This prevents the contact of the chemical solution with the conductive layer 151, for example, when the film formed after the pixel electrode including conductive layers 151 and 152 is removed by wet etching. Thus, galvanic corrosion in the pixel electrode can be suppressed, for example. Therefore, the display device 100 can be manufactured using a high-yield method, resulting in an inexpensive display device. Furthermore, defects in the display device 100 can be suppressed, making it a highly reliable display device. Note that in this specification, when describing the common elements among insulating layers 156R, 156G, and 156B, they are sometimes referred to as insulating layer 156.

[0341] As the conductive layer 151, a metallic material can be used, for example. Specifically, metals such as aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), neodymium (Nd), and alloys thereof can also be used.

[0342] As the conductive layer 152, an oxide containing one or more of indium, tin, zinc, gallium, titanium, aluminum, and silicon can be used. For example, conductive oxides containing one or more of indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, gallium-containing zinc oxide, titanium oxide, gallium-containing indium zinc oxide, aluminum-containing indium zinc oxide, silicon-containing indium tin oxide, and silicon-containing indium zinc oxide are preferred. In particular, silicon-containing indium tin oxide has a large work function, for example, 4.0 eV or more, so it is suitable for use as the conductive layer 152.

[0343] Conductive layer 151 and conductive layer 152 may each have a stacked structure containing multiple layers of different materials. In this case, conductive layer 151 may also include a layer using a material that can be used in conductive layer 152, such as a conductive oxide, and conductive layer 152 may also include a layer using a material that can be used in conductive layer 151, such as a metallic material. For example, when conductive layer 151 has a stacked structure of two or more layers, the layer in contact with conductive layer 152 may be a layer using a material that can be used in conductive layer 152.

[0344] Next, refer to Figures 10A to 15C The description has Figure 9A An example of a manufacturing method for the display device 100 with the shown structure. In the light-emitting device included in the display device 100, the organic layer is formed through a manufacturing process including a water treatment. By using the light-emitting device of one aspect of the present invention in the display device as an example of the present invention, a display device including a light-emitting device with reduced driving voltage and high luminous efficiency can be provided.

[0345] [Examples of Manufacturing Methods] Thin films (insulating films, semiconductor films, conductive films, etc.) constituting display devices can be formed using sputtering, chemical vapor deposition (CVD), vacuum evaporation, pulsed laser deposition (PLD), or atomic layer deposition (ALD). CVD methods include plasma-enhanced chemical vapor deposition (PECVD) and thermal CVD. Furthermore, metal-organic chemical vapor deposition (MOCVD) is one type of thermal CVD method.

[0346] In addition, the thin films (insulating films, semiconductor films, conductive films, etc.) constituting the display device can be formed using wet deposition methods such as spin coating, dip coating, spray coating, inkjet coating, dispenser coating, screen printing, offset printing, doctor knife coating, slot coating, roller coating, curtain coating, or doctor knife coating.

[0347] In particular, when manufacturing light-emitting devices, vacuum processes such as vapor deposition and solution processes such as spin coating and inkjet printing can be utilized. Examples of vapor deposition methods include physical vapor deposition (PVD) methods such as sputtering, ion plating, ion beam vapor deposition, molecular beam vapor deposition, and vacuum vapor deposition, as well as chemical vapor deposition (CVD). Specifically, functional layers (hole injection layer, hole transport layer, hole blocking layer, light-emitting layer, electron blocking layer, electron transport layer, and electron injection layer, etc.) comprising an organic compound layer can be formed using methods such as vapor deposition (vacuum vapor deposition, etc.), coating methods (dip coating, dye coating, rod coating, spin coating, spray coating, etc.), and printing methods (inkjet printing, screen printing, offset printing, flexographic printing, photogravure printing, or microcontact printing, etc.).

[0348] Furthermore, when processing the thin film constituting the display device, techniques such as lithography can be used. Alternatively, nanoimprinting, sandblasting, or stripping methods can be employed. Additionally, island-shaped thin films can be directly formed using deposition methods that employ masking techniques such as metal masks.

[0349] As a lithography technique, photolithography can be used, for example. Photolithography typically involves two methods. One is to form a resist mask on the thin film to be processed, for example, by etching the film, and then removing the resist mask. The other is to form a photosensitive thin film, expose and develop it, and then process the film into the desired shape.

[0350] In photolithography, the light used for exposure can be, for example, i-line (wavelength 365nm), g-line (wavelength 436nm), h-line (wavelength 405nm), or a mixture of these. Additionally, ultraviolet light, KrF lasers, or ArF lasers can also be used. Furthermore, immersion lithography can also be used. Extreme ultraviolet (EUV) light or X-rays can also be used as the light for exposure. Alternatively, an electron beam can be used instead of the light for exposure. Extreme ultraviolet light, X-rays, or electron beams allow for extremely fine processing and are therefore preferred. Furthermore, when exposure is performed by scanning with a beam such as an electron beam, a photomask is not required.

[0351] In the etching of thin films, dry etching, wet etching, or sandblasting methods can be used.

[0352] Furthermore, in the manufacturing process of light-emitting devices, organic compounds that are excited by absorbing light are used. These excited organic compounds sometimes have a high probability of reacting with oxygen or water in the atmosphere. In other words, when light of a wavelength absorbed by the organic compound is irradiated in the presence of oxygen, the organic compound may sometimes produce deterioration products.

[0353] Therefore, when processing a substrate with organic compounds formed using photolithography, it is preferable to perform the above processing under appropriately controlled lighting conditions when exposed to the atmosphere. Ideally, the above processing should be performed in an environment using illumination that does not excite the organic compounds through light absorption. However, to ensure that the illuminance or color rendering does not decrease in efficiency, it is preferable to use illumination with a wavelength of 600 nm or less, preferably 580 nm or less, at the shortest wavelength end of the emission spectrum of the light source.

[0354] For example, as illumination, a yellow lamp (fluorescent lamp or light-emitting diode (LED)) that does not emit light with wavelengths shorter than 500 nm is preferred. Furthermore, an orange lamp (fluorescent lamp or light-emitting diode (LED)) that does not emit light with wavelengths shorter than 530 nm is preferred. Low-pressure sodium lamps can also be used. Additionally, illumination employing optical filters capable of blocking light at short wavelengths can be used, such as incandescent lamps, fluorescent lamps, LEDs, halogen lamps, and sunlight. For example, bandpass filters and longpass filters (short-wavelength filtering filters) can be used as optical filters capable of blocking light at short wavelengths. Furthermore, by using the above-described illumination, the illuminance of the illumination light can be reduced.

[0355] First, such as Figure 10A An insulating layer 171 is formed on a substrate (not shown). Next, a conductive layer 172 and a conductive layer 179 are formed on the insulating layer 171, and an insulating layer 173 is formed on the insulating layer 171 to cover the conductive layers 172 and 179. Next, an insulating layer 174 is formed on the insulating layer 173, and an insulating layer 175 is formed on the insulating layer 174.

[0356] As a substrate, a substrate with heat resistance sufficient to withstand subsequent heat treatment can be used. When using an insulating substrate, glass substrates, quartz substrates, sapphire substrates, ceramic substrates, or organic resin substrates can be used. In addition, single-crystal semiconductor substrates or polycrystalline semiconductor substrates made of materials such as silicon or silicon carbide, compound semiconductor substrates made of materials such as silicon-germanium, SOI substrates, and other semiconductor substrates can also be used.

[0357] Next, as Figure 10AAs shown, openings leading to the conductive layer 172 are formed in insulating layers 175, 174, and 173. Then, a plug 176 is formed by embedding it into these openings.

[0358] Next, as Figure 10A As shown, a conductive film 151f, which will later become conductive layers 151R, 151G, 151B, and 151C, is formed on the plug 176 and the insulating layer 175. The conductive film 151f can be formed, for example, by sputtering or vacuum evaporation. Alternatively, a metallic material can be used as the conductive film 151f.

[0359] Next, as Figure 10A As shown, a conductive film 152f, which will later become conductive layers 152R, 152G, 152B, and 152C, is formed on a conductive film 151f. The conductive film 152f can be formed, for example, by sputtering or vacuum evaporation. Alternatively, a conductive oxide can be used as the conductive film 152f. Or, the conductive film 152f can be a laminated structure of a film using a metallic material and a film using a conductive oxide on that film. For example, the conductive film 152f can be a laminated structure of a film using titanium, silver, or a silver-containing alloy and a film using a conductive oxide on that film.

[0360] Furthermore, the conductive film 152f can be formed using the ALD method. Here, as the conductive film 152f, an oxide containing one or more metals selected from indium, tin, zinc, gallium, titanium, aluminum, and silicon can be used. The conductive film 152f can be formed by repeatedly performing a cycle of introducing a precursor (sometimes referred to as a precursor or metal precursor, etc.), purging the precursor, introducing an oxidant (sometimes referred to as a reactant, reactant, or non-metal precursor, etc.), and purging the oxidant. When forming a conductive film 152f from an oxide film containing multiple metals, such as indium tin oxide, the metal composition can be controlled by changing the number of cycles according to the type of precursor.

[0361] For example, in the case of depositing an indium tin oxide film as a conductive film 152f, after introducing an indium-containing precursor, the precursor is purged and an oxidant is introduced to form an In-O film. Next, after introducing a tin-containing precursor, the precursor is purged and an oxidant is introduced to form a Sn-O film. Here, by making the number of cycles for forming the In-O film greater than the number of cycles for forming the Sn-O film, the number of In atoms contained in the conductive film 152f can be greater than the number of Sn atoms.

[0362] Furthermore, for example, when depositing a zinc oxide film as the conductive film 152f, a Zn-O film is formed through the above process. Furthermore, for example, when depositing an aluminum-zinc oxide film as the conductive film 152f, both a Zn-O film and an Al-O film are formed through the above process. Furthermore, for example, when depositing a titanium oxide film as the conductive film 152f, a Ti-O film is formed through the above process. Furthermore, for example, when depositing an indium tin oxide film containing silicon as the conductive film 152f, an In-O film, a Sn-O film, and a Si-O film are formed through the above process. Furthermore, for example, when depositing a zinc oxide film containing gallium, both a Ga-O film and a Zn-O film are formed through the above process.

[0363] As indium-containing precursors, for example, triethylindium, trimethylindium, or [1,1,1-trimethyl-N-(trimethylsilyl)amide]-indium can be used. As tin-containing precursors, for example, tin chloride or tetra(dimethylamide)tin can be used. As zinc-containing precursors, for example, diethylzinc or dimethylzinc can be used. As gallium-containing precursors, for example, triethylgallium can be used. As titanium-containing precursors, for example, titanium chloride, tetra(dimethylamide)titanium, or tetraisopropyl titanate can be used. As aluminum-containing precursors, for example, aluminum chloride or trimethylaluminum can be used. As silicon-containing precursors, for example, trisilylamine, bis(diethylamino)silane, tri(dimethylamino)silane, bis(tert-butylamino)silane, or bis(ethylmethylamino)silane can be used. Additionally, water vapor, oxygen plasma, or ozone gas can be used as oxidants.

[0364] Next, as Figure 10A As shown, a photoresist mask 191 is formed on conductive films 151f and 152f. The photoresist mask 191 can be formed by coating a photosensitive material (photoresist) and then exposing and developing it.

[0365] Next, as Figure 10B As shown, for example, an etching method, specifically a dry etching method, is used to remove the conductive films 151f and 152f in areas that do not overlap with the resist mask 191, forming a pixel electrode including conductive layers 151 and 152. Note that if the conductive film 151f includes a layer of conductive oxide such as indium tin oxide, this layer can also be removed using a wet etching method. Thus, conductive layers 151 and 152 are formed. Note that, for example, when a portion of the conductive film 151f is removed using a dry etching method, a recess may sometimes be formed in the area of ​​the insulating layer 175 that does not overlap with the conductive layer 151.

[0366] Note that after forming conductive layers 152R, 152G, 152B, and 152C by processing conductive film 152f using lithography, conductive film 151f can also be processed using conductive layers 152R, 152G, 152B, and 152C as masks. Specifically, for example, after forming a resist mask, a portion of conductive film 152f can be removed using an etching method. For example, wet etching can be used to remove conductive film 152f. Note that dry etching can also be used to remove conductive film 152f. Then, wet etching is preferably used to remove conductive film 151f.

[0367] Here, it is preferable to perform a hydrophobic treatment on the conductive layer 152. This hydrophobic treatment can change the surface state of the object being treated from hydrophilic to hydrophobic, or it can increase the hydrophobicity of the surface. By performing a hydrophobic treatment on the conductive layer 152, the adhesion between the conductive layer 152 and the organic compound layer 103 to be formed in subsequent processes can be improved, thereby suppressing film peeling. Note that a hydrophobic treatment may not be performed.

[0368] Next, as Figure 10C As shown, the resist mask 191 is removed. The resist mask 191 can be removed, for example, by ashing using oxygen plasma. Alternatively, oxygen gas and Group 18 elements such as CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or He can be used. Alternatively, the resist mask 191 can also be removed by wet etching.

[0369] Next, as Figure 10D As shown, an insulating film 156f, which will later become insulating layers 156R, 156G, 156B, and 156C, is formed on conductive layers 151R, 152R, 151G, 152G, 151B, 152B, 151C, and 152C, and insulating layer 175. The insulating film 156f can be formed, for example, using CVD, ALD, sputtering, or vacuum evaporation.

[0370] Inorganic materials can be used for the insulating film 156f. For example, inorganic insulating films such as oxide insulating films, nitride insulating films, oxynitride insulating films, or oxynitride insulating films can be used as the insulating film 156f. For instance, silicon-containing insulating films such as oxide insulating films, nitride insulating films, oxynitride insulating films, or oxynitride insulating films can be used as the insulating film 156f. For example, silicon oxynitride can be used as the insulating film 156f.

[0371] Next, as Figure 10EAs shown, insulating film 156f is processed to form insulating layers 156R, 156G, 156B, and 156C. For example, insulating layer 156 can be formed by etching the top surface of insulating film 156f in a substantially uniform manner. This planarization process through uniform etching is also known as etch-back. Alternatively, insulating layer 156 can also be formed using photolithography.

[0372] Next, as Figure 11A As shown, an organic compound film 103Rf, which will later become an organic compound layer 103R, is formed on conductive layer 152R, conductive layer 152G, conductive layer 152B, insulating layer 156R, insulating layer 156G, insulating layer 156B and insulating layer 175.

[0373] like Figure 11A As shown, no organic compound film 103Rf is formed on the conductive layer 152C. For example, by using a mask that defines the deposition area (also called a zone mask or coarse metal mask, etc., to distinguish it from a high-precision metal mask), the organic compound film 103Rf can be deposited only in the desired area. By employing a deposition process using a zone mask and a processing process using a resist mask, the light-emitting device can be manufactured with a simpler process.

[0374] The organic compound film 103Rf can be formed, for example, by vapor deposition, specifically by vacuum vapor deposition. Alternatively, the organic compound film 103Rf can also be formed by methods such as transfer printing, printing, inkjet printing, or coating.

[0375] Next, as Figure 11A As shown, a sacrificial film 158Rf, which will later become a sacrificial layer 158R, and a mask film 159Rf, which will later become a mask layer 159R, are sequentially formed on an organic compound film 103Rf, a conductive layer 152C, and an insulating layer 175.

[0376] Note that in this embodiment, an example is shown where the mask film consists of a two-layer structure of sacrificial film 158Rf and mask film 159Rf. However, the mask film may have a single-layer structure or a stacked structure of three or more layers. Furthermore, in this specification and the like, the mask layer may also be referred to as the sacrificial layer.

[0377] By providing a sacrificial layer on the organic compound film 103Rf, the damage to the organic compound film 103Rf during the manufacturing process of the display device can be reduced, thereby improving the reliability of the light-emitting device.

[0378] The sacrificial film 158Rf is a film with high resistance to the processing conditions of the organic compound film 103Rf; specifically, it is a film with a large etch selectivity compared to the organic compound film 103Rf. The mask film 159Rf is a film with a large etch selectivity compared to the sacrificial film 158Rf.

[0379] Furthermore, the sacrificial film 158Rf and the mask film 159Rf are formed at a temperature lower than the heat resistance temperature of the organic compound film 103Rf. The substrate temperature during the formation of the sacrificial film 158Rf and the sacrificial film 159Rf is typically below 200°C, preferably below 150°C, more preferably below 120°C, further preferably below 100°C, and even more preferably below 80°C.

[0380] The sacrificial film 158Rf and the mask film 159Rf are preferably films that can be removed by wet etching. By using wet etching, the damage to the organic compound film 103Rf during the processing of the sacrificial film 158Rf and the mask film 159Rf can be reduced compared to using dry etching.

[0381] The sacrificial film 158Rf and the mask film 159Rf can be formed, for example, by sputtering, ALD (thermal ALD, PEALD), CVD, or vacuum evaporation. Alternatively, they can also be formed using the aforementioned wet deposition methods.

[0382] Furthermore, the sacrificial film 158Rf formed on the organic compound film 103Rf is preferably formed by a method that causes less damage to the organic compound film 103Rf compared to the formation of the mask film 159Rf. For example, the sacrificial film 158Rf is more preferably formed using the ALD method or vacuum evaporation method compared to sputtering.

[0383] As the sacrificial film 158Rf and the mask film 159Rf, one or more of the following can be used: metal film, alloy film, metal oxide film, semiconductor film, organic insulating film and inorganic insulating film.

[0384] The sacrificial film 158Rf and the mask film 159Rf can each be made of metallic materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium, and tantalum, or alloys containing such metallic materials. Low-melting-point materials such as aluminum or silver are particularly preferred. By using a metallic material capable of blocking ultraviolet light as one or both of the sacrificial film 158Rf and the mask film 159Rf, ultraviolet light irradiation onto the organic compound film 103Rf can be suppressed, thereby suppressing the degradation of the organic compound film 103Rf, which is therefore preferred.

[0385] In addition, metal oxides such as In-Ga-Zn oxide, indium oxide, In-Zn oxide, In-Sn oxide, indium titanium oxide (In-Ti oxide), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide (In-Ti-Zn oxide), indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide), and silicon-containing indium tin oxide can be used as sacrificial film 158Rf and mask film 159Rf respectively.

[0386] Note that element M (which is one or more of aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium) can also be used to replace gallium.

[0387] Furthermore, the sacrificial film and mask film are preferably made of a material that has light-shielding properties, especially against ultraviolet light. As the light-shielding material, various materials such as metals, insulators, semiconductors, and semi-metals with ultraviolet light-shielding properties can be used. Since part or all of the sacrificial film and mask film will be removed in subsequent processes, the sacrificial film and mask film are preferably films that can be processed by etching, and especially preferably films with good processability.

[0388] When using semiconductor materials such as silicon or germanium as sacrificial films and mask films, these materials have high affinity with semiconductor manufacturing processes and are therefore preferred. Alternatively, oxides or nitrides of the aforementioned semiconductor materials can be used. Alternatively, non-metallic materials such as carbon or their compounds can be used. Furthermore, metals such as titanium, tantalum, tungsten, chromium, and aluminum, or alloys containing one or more of these can be used. Additionally, oxides containing the aforementioned metals, such as titanium oxide or chromium oxide, or nitrides such as titanium nitride, chromium nitride, or tantalum nitride, can be used.

[0389] Furthermore, by using a film containing a material with UV-blocking properties as a sacrificial film or mask film, it is possible to suppress UV radiation from reaching the organic compound layer, for example, during the exposure process. By suppressing UV damage to the organic compound layer, the reliability of the light-emitting device can be improved.

[0390] Note that films containing materials with UV-blocking properties also produce the same effect when used as materials for the inorganic insulating film 125f described later.

[0391] Furthermore, various inorganic insulating films can be used as both the sacrificial film 158Rf and the mask film 159Rf. In particular, oxide insulating films exhibit higher adhesion to the organic compound film 103Rf compared to nitrided insulating films, and are therefore preferred. For example, inorganic insulating materials such as alumina, hafnium oxide, and silicon oxide can be used for both the sacrificial film 158Rf and the mask film 159Rf. For example, alumina films can be formed using the ALD method for both the sacrificial film 158Rf and the mask film 159Rf. Using the ALD method can reduce damage to the substrate (especially the organic compound layer), and is therefore preferred.

[0392] For example, an inorganic insulating film (e.g., an alumina film) formed using the ALD method can be used as the sacrificial film 158Rf, and an inorganic film (e.g., an In-Ga-Zn oxide film, an aluminum film, or a tungsten film) formed using the sputtering method can be used as the mask film 159Rf.

[0393] Furthermore, the same inorganic insulating film can be used for both the sacrificial layer 158Rf and the inorganic insulating layer 125 to be formed later. For example, an alumina film formed using the ALD method can be used for both the sacrificial layer 158Rf and the inorganic insulating layer 125. Here, the sacrificial layer 158Rf and the inorganic insulating layer 125 can be deposited under the same or different conditions. For example, by depositing the sacrificial film 158Rf under the same conditions as the inorganic insulating layer 125, the sacrificial film 158Rf can be formed as an insulating layer with high barrier properties against at least one of water and oxygen. On the other hand, the sacrificial film 158Rf is a layer that will be mostly or entirely removed in a later process, so it is preferably easy to process. Therefore, the sacrificial layer 158Rf is preferably deposited under conditions with a lower substrate temperature than that of the inorganic insulating layer 125.

[0394] Organic materials can also be used as one or both of the sacrificial film 158Rf and the mask film 159Rf. For example, materials that are chemically stable in solvents that are soluble in at least the uppermost layer of the organic compound film 103Rf can also be used as organic materials. In particular, materials soluble in water or alcohol can be used appropriately. When depositing the above-mentioned materials, it is preferable to apply the materials by a wet deposition method while the materials are dissolved in a solvent such as water or alcohol, and then perform a heat treatment to evaporate the solvent. At this time, it is preferable to perform the heat treatment under a reduced pressure atmosphere, thereby removing the solvent at a low temperature and for a short time, and reducing the thermal damage to the organic compound film 103Rf.

[0395] Sacrificial membrane 158Rf and mask membrane 159Rf can each be made of organic resins such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerol, pullulan, water-soluble cellulose, alcohol-soluble polyamide resin or perfluoropolymer, etc.

[0396] For example, an organic film (e.g., a PVA film) formed using any one of the above-described wet deposition methods can be used as the sacrificial film 158Rf, and an inorganic film (e.g., a silicon nitride film) formed using sputtering can be used as the mask film 159Rf.

[0397] Next, as Figure 11A As shown, a resist mask 190R is formed on a mask film 159Rf. The resist mask 190R can be formed by applying a photosensitive material (photoresist) and then exposing and developing it.

[0398] The 190R resist mask can utilize either positive or negative resist materials.

[0399] The resist mask 190R is provided at the position overlapping with the conductive layer 152R. Preferably, the resist mask 190R is also provided at the position overlapping with the conductive layer 152C. This can suppress damage to the conductive layer 152C during the manufacturing process of the display device. Note that the resist mask 190R may also be omitted from the conductive layer 152C. Furthermore, as... Figure 11A As shown in the cross-sectional view between B1 and B2, the resist mask 190R is preferably provided in such a way that it covers the end of the organic compound film 103Rf to the end of the conductive layer 152C (the end on the side of the organic compound film 103Rf).

[0400] Next, as Figure 11B As shown, a portion of the mask film 159Rf is removed using a resist mask 190R, thereby forming a mask layer 159R. The mask layer 159R remains on the conductive layers 152R and 152C. Then, the resist mask 190R is removed. Next, the mask layer 159R is used as a mask (also called a hard mask) to remove a portion of the sacrificial film 158Rf to form the sacrificial layer 158R.

[0401] The sacrificial film 158Rf and the mask film 159Rf can be processed by wet etching or dry etching, respectively. The processing of the sacrificial film 158Rf and the mask film 159Rf is preferably carried out by isotropic etching.

[0402] By using wet etching, damage to the organic compound film 103Rf can be reduced during the processing of the sacrificial film 158Rf and the mask film 159Rf compared to dry etching. When using wet etching, solutions such as developer, tetramethylammonium hydroxide aqueous solution (TMAH), dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or mixtures thereof are preferably used.

[0403] When processing the mask film 159Rf, the organic compound film 103Rf is not exposed, so the range of processing methods is wider compared to the case where the sacrificial film 158Rf is processed. Specifically, when processing the mask film 159Rf, even when using an oxygen-containing gas as the etching gas, the degradation of the organic compound film 103Rf can be suppressed.

[0404] Furthermore, when dry etching is used in the processing of the sacrificial film 158Rf, the degradation of the organic compound film 103Rf can be suppressed by not using an oxygen-containing gas as the etching gas. In the case of using dry etching, for example, a gas containing CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or Group 18 elements such as He is preferably used as the etching gas.

[0405] For example, when using an alumina film formed by the ALD method as the sacrificial film 158Rf, a portion of the sacrificial film 158Rf can be removed by dry etching using CHF3 and He, or CHF3, He, and CH4. Similarly, when using an In-Ga-Zn oxide film formed by sputtering as the mask film 159Rf, a portion of the mask film 159Rf can be removed by wet etching using dilute phosphoric acid. Alternatively, a portion of the mask film 159Rf can be removed by dry etching using CH4 and Ar. Furthermore, when using a tungsten film formed by sputtering as the mask film 159Rf, a portion of the mask film 159Rf can be removed by dry etching using SF6, CF4, and O2, or CF4, Cl2, and O2.

[0406] The resist mask 190R can be removed using the same method as the resist mask 191. The resist mask 190R can be removed, for example, by ashing using oxygen plasma. Alternatively, oxygen gas and Group 18 elements such as CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or He can be used. Alternatively, the resist mask 190R can be removed by wet etching. In this case, the sacrificial film 158Rf is on the outermost surface and the organic compound film 103Rf is not exposed, so damage to the organic compound film 103Rf can be suppressed during the removal process of the resist mask 190R. Furthermore, the range of removal methods for the resist mask 190R can be expanded.

[0407] Next, as Figure 11B As shown, the organic compound film 103Rf is processed to form the organic compound layer 103R. For example, the mask layer 159R and the sacrificial layer 158R are used as a hard mask to remove part of the organic compound film 103Rf to form the organic compound layer 103R.

[0408] Therefore, as Figure 11B As shown, a stacked structure of an organic compound layer 103R, a sacrificial layer 158R, and a mask layer 159R remains on the conductive layer 152R. Furthermore, conductive layers 152G and 152B are exposed.

[0409] Figure 11B An example is shown where the end of the organic compound layer 103R is located inside the end of the conductive layer 152R. By employing this structure, pixel miniaturization can be achieved, enabling the fabrication of high-definition displays. Note that although in Figure 11B Not shown in the figure, but sometimes the above etching process forms a recess in the area of ​​the insulating layer 175 that does not overlap with the organic compound layer 103R.

[0410] As described above, the resist mask 190R is preferably arranged such that it covers the end of the organic compound layer 103R between the dashed lines B1-B2 and the end of the conductive layer 152C (the end on one side of the organic compound layer 103R). Thus, as... Figure 11B As shown, the sacrificial layer 158R and the mask layer 159R are arranged such that they cover the end of the organic compound layer 103R to the end of the conductive layer 152C (the end on the side of the organic compound layer 103R) between the dashed lines B1-B2. Therefore, exposure of the insulating layer 175, for example, between the dashed lines B1-B2 can be suppressed. Consequently, exposure of the conductive layer 179 due to removal of a portion of the insulating layers 175, 174, and 173 by etching or the like can be suppressed. Therefore, unintentional electrical connections of the conductive layer 179 to other conductive layers can be suppressed. For example, short circuits occurring between the conductive layer 179 and the common second electrode 102 to be formed in subsequent processes can be suppressed.

[0411] The organic compound film 103Rf is preferably processed using anisotropic etching. Anisotropic dry etching is particularly preferred. Alternatively, wet etching may also be used.

[0412] When using dry etching, the degradation of the organic compound film 103Rf can be suppressed by not using an oxygen-containing gas as the etching gas.

[0413] Alternatively, oxygen-containing gases can be used as etching gases. When the etching gas contains oxygen, the etching rate can be increased. Therefore, etching can be performed at low power conditions while maintaining a sufficient etching rate. This suppresses damage to the organic compound film 103Rf. Furthermore, it suppresses defects such as the adhesion of reaction products generated during etching.

[0414] When using dry etching, it is preferable to use a gas containing one or more of Group 18 elements such as H2, CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, and He or Ar as the etching gas. Alternatively, it is preferable to use a gas containing one or more of the above-mentioned gases and oxygen as the etching gas. Oxygen gas may also be used as the etching gas. Specifically, for example, a gas containing H2 and Ar or a gas containing CF4 and He can be used as the etching gas. Furthermore, for example, a gas containing CF4, He, and oxygen can be used as the etching gas. Additionally, for example, a gas containing H2 and Ar and an oxygen-containing gas can be used as the etching gas.

[0415] As described above, in one aspect of the present invention, a mask layer 159R is formed by forming a resist mask 190R on a mask film 159Rf and using the resist mask 190R to remove a portion of the hard mask film 159Rf. Then, an organic compound layer 103R is formed by using the mask layer 159R as a mask to remove a portion of the organic compound film 103Rf. Therefore, it can be said that the organic compound layer 103R is formed by processing the organic compound film 103Rf using lithography. Alternatively, a portion of the organic compound film 103Rf can be removed using the resist mask 190R. Then, the resist mask 190R can also be removed.

[0416] Next, for example, it is preferable to perform a hydrophobic treatment on the conductive layer 152G. During the processing of the organic compound film 103Rf, the surface state of the conductive layer 152G sometimes becomes hydrophilic. By performing a hydrophobic treatment on the conductive layer 152G, for example, the adhesion between the conductive layer 152G and the layer to be formed in a later process (here, the organic compound layer 103G) can be improved, thereby suppressing film peeling. Note that a hydrophobic treatment may not be performed.

[0417] Next, as Figure 12A As shown, an organic compound film 103Gf, which will later become an organic compound layer 103G, is formed on conductive layer 152G, conductive layer 152B, insulating layer 156R, insulating layer 156G, insulating layer 156B, mask layer 159R, and insulating layer 175.

[0418] The organic compound membrane 103Gf can be formed using the same method as that used in forming the organic compound membrane 103Rf. Furthermore, the organic compound membrane 103Gf can have the same structure as the organic compound membrane 103Rf.

[0419] Next, as Figure 12A As shown, a sacrificial film 158Gf, which will later become a sacrificial layer 158G, and a mask film 159Gf, which will later become a mask layer 159G, are sequentially formed on an organic compound film 103Gf and a mask layer 159R. Then, a photoresist mask 190G is formed. The materials and formation methods of the sacrificial film 158Gf and the mask film 159Gf are the same as those applicable to the sacrificial film 158Rf and the mask film 159Rf. The materials and formation methods of the photoresist mask 190G are the same as those applicable to the photoresist mask 190R.

[0420] The resist mask 190G is positioned at the location where it overlaps with the conductive layer 152G.

[0421] Next, as Figure 12B As shown, a portion of the mask film 159Gf is removed using a resist mask 190G, thereby forming a mask layer 159G. The mask layer 159G remains on the conductive layer 152G. Then, the resist mask 190G is removed. Next, the mask layer 159G is used as part of the mask removal sacrificial film 158Gf to form a sacrificial layer 158G. Next, the organic compound film 103Gf is processed to form an organic compound layer 103G. For example, the mask layer 159G and the sacrificial layer 158G are used as part of the hard mask removal organic compound film 103Gf to form the organic compound layer 103G.

[0422] Therefore, as Figure 12B As shown, a stacked structure of an organic compound layer 103G, a sacrificial layer 158G, and a mask layer 159G remains on the conductive layer 152G. Furthermore, the mask layer 159R and the conductive layer 152B are exposed.

[0423] Next, for example, it is preferable to perform a hydrophobic treatment on the conductive layer 152B. During the processing of the organic compound film 103Gf, the surface state of the conductive layer 152B sometimes becomes hydrophilic. By performing a hydrophobic treatment on the conductive layer 152B, for example, the adhesion between the conductive layer 152B and the layer to be formed in a later process (here, the organic compound layer 103B) can be improved, thereby suppressing film peeling. Note that a hydrophobic treatment may not be performed.

[0424] Next, as Figure 12CAs shown, an organic compound film 103Bf, which will later become an organic compound layer 103B, is formed on conductive layer 152B, insulating layer 156R, insulating layer 156G, insulating layer 156B, mask layer 159R, mask layer 159G and insulating layer 175.

[0425] The organic compound membrane 103Bf can be formed using the same method as that used in forming the organic compound membrane 103Rf. Furthermore, the organic compound membrane 103Bf can have the same structure as the organic compound membrane 103Rf.

[0426] Next, as Figure 12C As shown, a sacrificial film 158Bf, which will later become a sacrificial layer 158B, and a mask film 159Bf, which will later become a mask layer 159B, are sequentially formed on an organic compound film 103Bf and a mask layer 159R. Then, a photoresist mask 190B is formed. The materials and formation methods of the sacrificial film 158Bf and the mask film 159Bf are the same as those applicable to the sacrificial film 158Rf and the mask film 159Rf. The materials and formation method of the photoresist mask 190B are the same as those applicable to the photoresist mask 190R.

[0427] The resist mask 190B is disposed at a position overlapping the conductive layer 152B.

[0428] Next, as Figure 12D As shown, a portion of the mask film 159Bf is removed using a resist mask 190B, thereby forming a mask layer 159B. The mask layer 159B remains on the conductive layer 152B. Then, the resist mask 190B is removed. Next, the mask layer 159B is used as part of the mask removal sacrificial film 158Bf to form a sacrificial layer 158B. Next, the organic compound film 103Bf is processed to form an organic compound layer 103B. For example, the mask layer 159B and the sacrificial layer 158B are used as part of the hard mask removal organic compound film 103Bf to form the organic compound layer 103B.

[0429] Therefore, as Figure 12D As shown, a stacked structure of an organic compound layer 103B, a sacrificial layer 158B, and a mask layer 159B remains on the conductive layer 152B. Furthermore, mask layers 159R and 159G are exposed.

[0430] Note that the side surfaces of organic compound layers 103R, 103G, and 103B are preferably perpendicular to or substantially perpendicular to the surface to which they are formed. For example, the angle formed between the surface to which they are formed and these side surfaces is preferably 60 degrees or more and 90 degrees or less.

[0431] As described above, the distance between two adjacent organic compound layers 103R, 103G, and 103B formed using photolithography can be reduced to 8 μm or less, 5 μm or less, 3 μm or less, 2 μm or less, or 1 μm or less. This distance can be specified, for example, based on the distance between the opposite ends of two adjacent organic compound layers 103R, 103G, and 103B. Thus, by reducing the distance between the island-shaped organic compound layers, a display device with high resolution and a large aperture ratio can be provided. Furthermore, the distance between the first electrodes of adjacent light-emitting devices can also be reduced, for example, to 10 μm or less, 8 μm or less, 5 μm or less, 3 μm or less, or 2 μm or less. Moreover, the distance between the first electrodes of adjacent light-emitting devices is preferably 2 μm or more and 5 μm or less.

[0432] Next, as Figure 13A As shown, it is preferable to remove mask layers 159R, 159G, and 159B. Depending on subsequent processes, sacrificial layers 158R, 158G, 158B, mask layers 159R, 159G, and 159B may sometimes remain in the display device. By removing mask layers 159R, 159G, and 159B at this stage, it is possible to prevent them from remaining in the display device. For example, when conductive materials are used in mask layers 159R, 159G, and 159B, by removing them beforehand, leakage current and capacitance formation due to residual mask layers 159R, 159G, and 159B can be suppressed.

[0433] Note that although this embodiment uses the case where mask layers 159R, 159G, and 159B are removed as an example, it is also possible to proceed with the next process without removing mask layers 159R, 159G, and 159B. For example, when mask layers 159R, 159G, and 159B contain the aforementioned material with UV-blocking properties, proceeding to the next process without removing these mask layers can protect the organic compound layer from UV radiation, which is therefore preferred.

[0434] The mask layer removal process can utilize the same method as the mask film processing process. By using wet etching, compared to using dry etching, damage to the organic compound layers 103R, 103G, and 103B can be reduced during mask layer removal.

[0435] Alternatively, the mask layer can be removed by dissolving it in a solvent such as water or alcohol. Examples of alcohols include ethanol, methanol, isopropanol (IPA), or glycerol.

[0436] After removing the mask layer, a drying process can be performed to remove water contained in organic compound layers 103R, 103G, and 103B, as well as water adsorbed on the surfaces of organic compound layers 103R, 103G, and 103B. For example, heating treatment can be performed under an inert gas atmosphere or a reduced pressure atmosphere. The heating treatment can be performed at a substrate temperature of 50°C or higher and 200°C or lower, preferably 60°C or higher and 150°C or lower, and more preferably 70°C or higher and 120°C or lower. Using a reduced pressure atmosphere allows for drying at lower temperatures, which is therefore preferred.

[0437] Next, as Figure 13B As shown, an inorganic insulating film 125f, which will later become an inorganic insulating layer 125, is formed by covering organic compound layer 103R, organic compound layer 103G, organic compound layer 103B, sacrificial layer 158R, sacrificial layer 158G, and sacrificial layer 158B.

[0438] As described later, the insulating film, which will later become the insulating layer 127, is formed by contacting the top surface of the inorganic insulating film 125f. Therefore, the top surface of the inorganic insulating film 125f preferably has high affinity with the material used for the insulating film (e.g., a photosensitive resin composition containing acrylic resin). To improve this affinity, it is preferable to perform a surface treatment to make the top surface of the inorganic insulating film 125f hydrophobic (or to improve its hydrophobicity). For example, it is preferable to use a silanizing agent such as hexamethyldisilazane (HMDS). By making the top surface of the inorganic insulating film 125f hydrophobic in this way, the insulating film 127f can be formed with high adhesion. In addition, the above-described hydrophobic treatment can also be performed as a surface treatment.

[0439] Next, as Figure 13C As shown, an insulating film 127f, which will later become an insulating layer 127, is formed on an inorganic insulating film 125f.

[0440] The inorganic insulating film 125f and the insulating film 127f are preferably deposited by a formation method that causes less damage to the organic compound layers 103R, 103G, and 103B. In particular, the inorganic insulating film 125f is formed in contact with the sides of the organic compound layers 103R, 103G, and 103B, so the inorganic insulating film 125f is preferably deposited by a formation method that causes less damage to the organic compound layers 103R, 103G, and 103B than when the insulating film 127f is deposited.

[0441] Furthermore, the inorganic insulating film 125f and the insulating film 127f are each formed at a temperature lower than the heat resistance temperature of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B. By increasing the substrate temperature during deposition, an inorganic insulating film 125f with low impurity concentration and high barrier properties against at least one of water and oxygen can be formed even with a thin thickness.

[0442] The substrate temperature for forming the inorganic insulating film 125f and the insulating film 127f is preferably 60°C or higher, 80°C or higher, 100°C or higher, or 120°C or higher and 200°C or lower, 180°C or lower, 160°C or lower, 150°C or lower, or 140°C or lower.

[0443] As the inorganic insulating film 125f, it is preferable to form an insulating film with a thickness of 3 nm or more, 5 nm or more, or 10 nm or more and a thickness of 200 nm or less, 150 nm or less, 100 nm or less, or 50 nm or less within the above-mentioned substrate temperature range.

[0444] The inorganic insulating film 125f is preferably formed using the ALD method, for example. The ALD method reduces deposition damage and allows for the deposition of films with high coverage, making it preferred. For example, an alumina film is preferably formed using the ALD method as the inorganic insulating film 125f.

[0445] In addition, the inorganic insulating film 125f can also be formed using sputtering, CVD, or PECVD methods, which have higher deposition rates than ALD. This allows for the production of highly reliable display devices with high productivity.

[0446] The insulating film 127f is preferably formed using the wet deposition method described above. The insulating film 127f is preferably formed, for example, by spin coating using a photosensitive material, and more specifically, preferably by using a photosensitive resin composition containing acrylic resin.

[0447] For example, it is preferable to use a resin composition containing a polymer, an acid-generating agent, and a solvent to form the insulating film 127f. The polymer is formed using one or more monomers and has a structure in which one or more structural units (also called constituent units) are repeated regularly or irregularly. As the acid-generating agent, one or both of a compound that generates acid by irradiation and a compound that generates acid by heating can be used. The resin composition may also contain one or more of a photosensitizer, sensitizer, catalyst, adhesive aid, surfactant, and antioxidant.

[0448] Furthermore, it is preferable to perform a heat treatment (also known as pre-baking) after forming the insulating film 127f. This heat treatment is performed at a temperature lower than the heat resistance temperature of the organic compound layers 103R, 103G, and 103B. The substrate temperature during the heat treatment is preferably 50°C or higher and 200°C or lower, more preferably 60°C or higher and 150°C or lower, and even more preferably 70°C or higher and 120°C or lower. This removes the solvent from the insulating film 127f.

[0449] Next, exposure is performed to expose a portion of the insulating film 127f to visible light or ultraviolet light. Here, when a positive photosensitive resin composition containing acrylic resin is used for the insulating film 127f, visible light or ultraviolet light is irradiated onto the area where the insulating layer 127 will not be formed in a later process. The insulating layer 127 is formed in the area sandwiched between any two of the conductive layers 152R, 152G, and 152B, and around the conductive layer 152C. Therefore, visible light or ultraviolet light is irradiated onto the conductive layers 152R, 152G, 152B, and 152C. Note that when a negative photosensitive material is used for the insulating film 127f, visible light or ultraviolet light is irradiated onto the area where the insulating layer 127 will be formed.

[0450] The width of the insulating layer 127 to be formed later can be controlled by the area exposed to the insulating film 127f. In this embodiment, the insulating layer 127 is processed such that it has a portion overlapping the top surface of the conductive layer 151.

[0451] The light used for exposure preferably has an i-line (wavelength 365 nm). Alternatively, the light used for exposure may also have at least one of a g-line (wavelength 436 nm) and an h-line (wavelength 405 nm).

[0452] Here, by providing an oxygen-blocking insulating layer (such as an alumina film) as one or both of the sacrificial layer 158 (sacrificial layer 158R, sacrificial layer 158G, and sacrificial layer 158B) and the inorganic insulating film 125f, oxygen diffusion to the organic compound layers 103R, 103G, and 103B can be suppressed. When light (visible light or ultraviolet light) irradiates the organic compound layers, the organic compounds contained in the organic compound layers may become excited and promote reaction with oxygen in the atmosphere. Specifically, when light (visible light or ultraviolet light) irradiates the organic compound layers in an oxygen-containing atmosphere, oxygen may bond to the organic compounds contained in the organic compound layers. By providing the sacrificial layer 158 and the inorganic insulating film 125f on the island-like organic compound layers, the bonding of oxygen in the atmosphere to the organic compounds contained in the organic compound layers can be suppressed.

[0453] Next, as Figure 14AAs shown, the exposed areas in the insulating film 127f are removed by development to form the insulating layer 127a. The insulating layer 127a is formed in the area sandwiched by any two of the conductive layers 152R, 152G, and 152B, and in the area surrounding the conductive layer 152C. Here, when acrylic resin is used for the insulating film 127f, an alkaline solution, such as TMAH, can be used as the developing solution.

[0454] Next, residues from the development process (so-called scum) can also be removed. For example, residues can be removed by ashing using oxygen plasma.

[0455] Alternatively, etching can be performed to adjust the surface height of the insulating layer 127a. The insulating layer 127a can also be processed, for example, by ashing using oxygen plasma. Furthermore, when a non-photosensitive material is used as the insulating film 127f, the surface height of the insulating film 127f can also be adjusted, for example, by this ashing process.

[0456] Next, as Figure 14B As shown, an etching process is performed using insulating layer 127a as a mask to remove a portion of the inorganic insulating film 125f, thereby thinning a portion of the sacrificial layers 158R, 158G, and 158B. This forms an inorganic insulating layer 125 beneath insulating layer 127a. Furthermore, the surfaces of the thinner portions of sacrificial layers 158R, 158G, and 158B are exposed. The etching process using insulating layer 127a as a mask is sometimes referred to as the first etching process.

[0457] The first etching process can be performed by dry etching or wet etching. Alternatively, when the inorganic insulating film 125f is deposited using the same material as the sacrificial layers 158R, 158G, and 158B, the first etching process can be performed in one step, which is preferred.

[0458] By using the tapered insulating layer 127a as a mask for etching, the sides of the inorganic insulating layer 125 and the upper ends of the sides of the sacrificial layers 158R, 158G and 158B can be more easily made into a tapered shape.

[0459] When performing dry etching, chlorine-based gases are preferred. One or more of the following chlorine-based gases can be used: Cl2, BCl3, SiCl4, and CCl4. Alternatively, one or more of the following gases can be appropriately added to the chlorine-based gas: oxygen, hydrogen, helium, and argon. By utilizing dry etching, regions with thin sacrificial layers 158R, 158G, and 158B can be formed with excellent in-plane uniformity.

[0460] As a dry etching apparatus, a dry etching apparatus with a high-density plasma source can be used. For example, an inductively coupled plasma (ICP) etching apparatus can be used as a dry etching apparatus with a high-density plasma source. Alternatively, a capacitively coupled plasma (CCP) etching apparatus including parallel planar electrodes can be used. The capacitively coupled plasma etching apparatus including parallel planar electrodes can also employ a structure in which a high-frequency voltage is applied to one of the parallel planar electrodes. Alternatively, a structure in which multiple different high-frequency voltages are applied to one of the parallel planar electrodes can be used. Alternatively, a structure in which high-frequency voltages of the same frequency are applied to each of the parallel planar electrodes can be used. Alternatively, a structure in which high-frequency voltages of different frequencies are applied to each of the parallel planar electrodes can be used.

[0461] Furthermore, during dry etching, byproducts generated during the process may sometimes be deposited on the top and sides of the insulating layer 127a. As a result, components of the etching gas, the inorganic insulating film 125f, and the sacrificial layers 158R, 158G, and 158B may sometimes be included in the insulating layer 127 after the display device is completed.

[0462] Furthermore, wet etching is preferred for the first etching process. Compared to dry etching, wet etching further reduces damage to the organic compound layers 103R, 103G, and 103B. For example, wet etching can be performed using an alkaline solution. For instance, TMAH of an alkaline solution can be used in the wet etching of the alumina film. In this case, wet etching can be performed by coating. Additionally, when the inorganic insulating film 125f is deposited using the same material as the sacrificial layers 158R, 158G, and 158B, the above etching process can be performed in a single step, which is therefore preferred.

[0463] In the first etching process, the sacrificial layers 158R, 158G, and 158B are not completely removed; the etching process is stopped when the thickness is reduced. Thus, by leaving corresponding sacrificial layers 158R, 158G, and 158B on the organic compound layers 103R, 103G, and 103B, damage to the organic compound layers 103R, 103G, and 103B can be prevented during subsequent processing steps.

[0464] Next, the entire substrate is preferably exposed to visible or ultraviolet light onto the insulating layer 127a. The energy density of this exposure is preferably higher than 0 mJ / cm².2 And it is 800mJ / cm 2 Below, a value higher than 0 mJ / cm is preferred. 2 And it is 500mJ / cm 2 The following applies. By performing this exposure after development, the transparency of the insulating layer 127a can sometimes be improved. Additionally, the substrate temperature required for the subsequent heat treatment to deform the insulating layer 127a into a conical shape can sometimes be reduced.

[0465] Here, by providing oxygen-barrier insulating layers (such as an alumina film) as sacrificial layers 158R, 158G, and 158B, oxygen diffusion to the organic compound layers 103R, 103G, and 103B can be suppressed. When light (visible light or ultraviolet light) irradiates the organic compound layers, the organic compounds contained in the organic compound layers may sometimes become excited and promote reaction with oxygen in the atmosphere. Specifically, when light (visible light or ultraviolet light) irradiates the organic compound layers in an oxygen-containing atmosphere, oxygen may bond to the organic compounds contained in the organic compound layers. By providing sacrificial layers 158R, 158G, and 158B on the island-shaped organic compound layers, the bonding of oxygen in the atmosphere to the organic compounds contained in the organic compound layers can be suppressed.

[0466] Next, a heat treatment (also known as post-baking) is performed. This heat treatment deforms the insulating layer 127a into an insulating layer 127 with a tapered shape on its sides. Figure 14C The heat treatment is performed at a temperature lower than the heat resistance temperature of the organic compound layer. The heat treatment can be performed at a substrate temperature of 50°C or higher and 200°C or lower, preferably 60°C or higher and 150°C or lower, and more preferably 70°C or higher and 130°C or lower. The heating atmosphere can be either atmospheric or an inactive gas. Furthermore, the heating atmosphere can be either atmospheric or a reduced-pressure atmosphere. In this heat treatment process, it is preferable to increase the substrate temperature compared to the heat treatment (pre-baking) after the formation of the insulating film 127f. This improves the adhesion between the insulating layer 127 and the inorganic insulating layer 125, and also improves the corrosion resistance of the insulating layer 127.

[0467] In the first etching process, by not completely removing the sacrificial layers 158R, 158G, and 158B, leaving them in a thinned state, damage and deterioration of the organic compound layers 103R, 103G, and 103B can be prevented during the heat treatment. This improves the reliability of the light-emitting device.

[0468] Note that, depending on the material of the insulating layer 127 and the temperature, time, and atmosphere of the post-baking process, the side surface of the insulating layer 127 may sometimes have a concave curved shape. For example, the higher the temperature or the longer the time in the post-baking conditions, the more easily the shape of the insulating layer 127 can change, thus sometimes resulting in a concave curved shape.

[0469] Next, as Figure 15A As shown, the insulating layer 127 is used as a mask for etching, removing a portion of the sacrificial layers 158R, 158G, and 158B. Note that a portion of the inorganic insulating layer 125 is sometimes also removed. This creates openings in the sacrificial layers 158R, 158G, and 158B, exposing the top surfaces of the organic compound layers 103R, 103G, 103B, and the conductive layer 152C. Furthermore, the etching process using the insulating layer 127 as a mask is sometimes referred to as the second etching process.

[0470] The ends of the inorganic insulating layer 125 are covered by the insulating layer 127. Additionally, Figure 15A An example is shown where a portion of the end of the sacrificial layer 158G (specifically, the tapered portion formed by the first etching process) is covered by the insulating layer 127 and the tapered portion formed by the second etching process is exposed.

[0471] When the inorganic insulating layer 125 and the mask layer are etched in a single process after post-baking without a first etching process, voids may sometimes form as the inorganic insulating layer 125 and the mask layer below the end of the insulating layer 127 disappear due to lateral etching. These voids create unevenness on the surface where the second electrode 102 is formed, making it easier for the second electrode 102 to break. Even if voids are formed by lateral etching of the inorganic insulating layer 125 and the mask layer after the first etching process, these voids can be filled by the insulating layer 127 during subsequent post-baking. Then, in the second etching process, the mask layer, which is further thinned, is etched, resulting in less lateral etching and a lower likelihood of void formation; even if voids do form, they can be minimized. Therefore, the surface where the second electrode 102 is formed can be made flatter.

[0472] Alternatively, the insulating layer 127 may also cover the entire end of the sacrificial layer 158G. For example, the end of the insulating layer 127 may sometimes droop down and cover the end of the sacrificial layer 158G. Additionally, for example, the end of the insulating layer 127 may sometimes contact the top surface of at least one of the organic compound layers 103R, 103G, and 103B. As described above, the shape of the insulating layer 127 can sometimes be easily varied when the insulating layer 127a is not exposed after development.

[0473] The second etching process is performed using wet etching. Compared to dry etching, wet etching further reduces damage to the organic compound layers 103R, 103G, and 103B. Wet etching can be performed using an alkaline solution such as TMAH.

[0474] On the other hand, during the second etching process using wet etching, if there are issues such as poor adhesion between the organic compound layer 103 and other layers, resulting in gaps at the interfaces between the organic compound layer 103 and the sacrificial layer 158, between the organic compound layer 103 and the inorganic insulating layer 125, and between the organic compound layer 103 and the insulating layer 175, the etching solution used in the second etching process may sometimes enter these gaps and come into contact with the pixel electrode. Here, when the etching solution comes into contact with both conductive layers 151 and 152, the conductive layer with the lower natural potential may sometimes corrode due to galvanic corrosion. For example, when aluminum is used as conductive la...

Claims

1. A light-emitting device, comprising: First electrode; Second electrode; Emissive layer; as well as First floor, The light-emitting layer is located between the first electrode and the second electrode. The first layer is located between the light-emitting layer and the second electrode. The first layer comprises at least one of a first organic compound, a second organic compound, and a metal and a metal compound. Furthermore, the absorption spectrum of the first mixed film containing at least one of the first organic compound, the second organic compound, and the metal and metal compound has a wavelength region in which its absorption intensity is larger than that of the absorption spectrum of the second mixed film containing either the first organic compound or the second organic compound and at least one of the metal and metal compound and whose thickness difference from that of the first mixed film is less than 10%.

2. A light-emitting device, comprising: First electrode; Second electrode; Emissive layer; as well as First floor, The light-emitting layer is located between the first electrode and the second electrode. The first layer is located between the light-emitting layer and the second electrode. The first layer comprises at least one of a first organic compound, a second organic compound, and a metal and a metal compound. The absorption spectrum of a first mixed film comprising at least one of the first organic compound, the second organic compound, and the metal and metal compounds has a wavelength region in which its absorption intensity is larger than that of a third mixed film comprising at least one of the first organic compound and the metal and metal compounds and whose thickness difference from that of the first mixed film is less than 10%. Furthermore, the absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is larger than that of the fourth mixed film, which contains at least one of the second organic compound and the metal and metal compound and whose thickness difference from that of the first mixed film is less than 10%.

3. A light-emitting device, comprising: First electrode; Second electrode; First luminescent layer; First layer; as well as Second light-emitting layer, The first light-emitting layer and the second light-emitting layer are located between the first electrode and the second electrode. The first layer is located between the first light-emitting layer and the second light-emitting layer. The first layer comprises at least one of a first organic compound, a second organic compound, and a metal and a metal compound. Furthermore, the absorption spectrum of the first mixed film containing at least one of the first organic compound, the second organic compound, and the metal and metal compound has a wavelength region in which its absorption intensity is larger than that of the absorption spectrum of the second mixed film containing either the first organic compound or the second organic compound and at least one of the metal and metal compound and whose thickness difference from that of the first mixed film is less than 10%.

4. A light-emitting device, comprising: First electrode; Second electrode; First luminescent layer; First layer; as well as Second light-emitting layer, The first light-emitting layer and the second light-emitting layer are located between the first electrode and the second electrode. The first layer is located between the first light-emitting layer and the second light-emitting layer. The first layer comprises at least one of a first organic compound, a second organic compound, and a metal and a metal compound. The absorption spectrum of a first mixed film comprising at least one of the first organic compound, the second organic compound, and the metal and metal compounds has a wavelength region in which its absorption intensity is larger than that of a third mixed film comprising at least one of the first organic compound and the metal and metal compounds and whose thickness difference from that of the first mixed film is less than 10%. Furthermore, the absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is larger than that of the fourth mixed film, which contains at least one of the second organic compound and the metal and metal compound and whose thickness difference from that of the first mixed film is less than 10%.

5. The light-emitting device according to claim 1 or 3, The absorption spectrum of the first mixed membrane has a wavelength region in which its absorption intensity is greater than that of the second mixed membrane in a region with a longer wavelength end than that of the absorption spectrum of the membrane containing the organic compound.

6. The light-emitting device according to claim 2 or 4, The absorption spectrum of the first mixed film has a wavelength region in which its absorption intensity is greater than that of the third mixed film in a region longer than the absorption spectrum of the film containing the first organic compound on the longer wavelength side. Furthermore, the absorption spectrum of the first mixed membrane has a wavelength region in which its absorption intensity is greater than that of the fourth mixed membrane in a region with a longer wavelength end than that of the absorption spectrum of the membrane containing the second organic compound.

7. The light-emitting device according to any one of claims 1 to 4, The metal and metal compound wherein at least one of them contains a metallic element belonging to any one of groups 3 to 14 of the periodic table.

8. The light-emitting device according to claim 7, The metal and metal compound wherein at least one of them contains a metal element belonging to Group 3, Group 11 or Group 13 of the periodic table.

9. The light-emitting device according to any one of claims 1 to 4, further comprising: The second floor, The second layer is located between the first layer and the second electrode. The second layer contains a third organic compound and a fourth organic compound. The third organic compound is an organic compound with a π-electron-rich heteroaromatic ring or an aromatic amine. Furthermore, the fourth organic compound has at least one of a halogen group and a cyano group.

10. The light-emitting device according to any one of claims 1 to 4, The LUMO energy level of the first organic compound is higher than that of the second organic compound.

11. The light-emitting device according to any one of claims 1 to 4, The HOMO energy level of the first organic compound is higher than that of the second organic compound.

12. The light-emitting device according to any one of claims 1 to 4, Both the first organic compound and the second organic compound have heteroaromatic rings.

13. The light-emitting device according to claim 12, The heteroaromatic rings of the first organic compound and the second organic compound each independently comprise at least one of the following: pyridine ring, pyrazine ring, pyrimidine ring, pyridazine ring, triazine ring, imidazole ring, pyrazole ring, oxazole ring, thiazole ring, and triazole ring.

14. The light-emitting device according to claim 12, The first organic compound has an electron-donating group.

15. The light-emitting device according to claim 14, The electron-donating group is at least one of alkyl, alkoxy, aryloxy, alkylamino, arylamino, and heterocyclic amino groups.

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